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Exam
Name___________________________________
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response. 1)An agricultural researcher wishes to compare the yield of four different varieties of wheat. 64 plots of land are available for an experiment. On each plot of land one of the varieties of wheat will be grown. At the end of the experiment the yield for the different varieties will be compared. 32 of the plots are at one site (site A) and the other 32 are at another site (site B). The soil at site A differs significantly from the soil at site B. If the researcher wishes to design an experiment using randomized block design, how could the wheat varieties be assigned to the different plots?
Answer:Answers will vary. Possible answer: Randomly divide the 32 plots at site A into four groups of 8 plots each. Randomly assign each group of plots to a different variety of wheat. Randomly divide the 32 plots at site B into four groups of 8 plots each. Randomly assign each group of plots to a different variety of wheat. Explanation:
2)Describe the steps involved when using stratified random sampling with proportional allocation. What are the advantages of this sampling method?
Answer:Answers will vary. Possible answer: The population is first divided into subpopulations (strata). From each stratum, a simple random sample is obtained whose size is proportional to the size of the stratum. The advantage of this method is that it ensures that no stratum is missed. Explanation:
3)A college lecturer has devised a new method of teaching a particular mathematical concept and wishes to try out this teaching method on a representative sample of his students. There are 76 students in his class and he wishes to obtain a simple random sample of 25 of them. Describe a method which would be unlikely to yield a representative sample.
Answer:Answers will vary. Possible answer: The lecturer stands at the door of his classroom and tells the first 25 students to arrive to class that they are invited to a special bonus session of class to be held at some upcoming date. This is unlikely to yield a representative sample as the students who show up to class first could possibly be the ones who are more conscientious and hard-working. Or, the students may refuse to volunteer for an extra class period, so the lecturer's sample would be too small to be a representative sample. Explanation:
4)A political researcher wishes to gauge political sentiment regarding a proposed tax cut. He obtains a list of 1000 email addresses from an internet provider, uses a random number table to select a random sample of 100 of these addresses, emails the people in the sample and requests that they respond to his questions by email. Do you think that the group of people who respond is likely to be representative of all registered voters? Explain your answer.
Answer:No; explanations will vary. Possible answer: the sample was obtained from among people who own a computer. That group is likely to include relatively wealthy people who are more likely to favor a tax cut. Furthermore, the group includes those who chose voluntarily to respond. People who respond voluntarily are likely to have stronger opinions than the average voter. Explanation:
5)A store manager wishes to determine whether his customers would be prepared to pay a little extra for organic produce. He uses a random number table to choose 50 random numbers between 1 and 200. He stands outside the store on a Monday morning between 9:00 a.m. and 12:00 noon and interviews the people corresponding to the random numbers. For example random number 82 would correspond to the 82nd person to arrive. Do you think that the sample obtained in this way will be representative of all the store's customers?
Answer:No; explanations will vary. Possible answer: the sample was obtained from among people shopping on a Monday morning. That group is likely to include a relatively large number of people who do no have full time jobs and a relatively large number of parents. This group may tend to have different views than the entire population of customers. People with young children, for example, may be more concerned than most about the health effects of produce grown with pesticides. Explanation:
6)The residents of one town are classified by a social scientist as follows.
Lower income: 4320 Middle income: 1520 Upper income: 2160
The scientist wishes to pick a sample of 200 of the residents for a study. Describe a method for selecting the sample which involves stratified sampling with proportional allocation.
Answer:Answers will vary. Possible answer: Proportional allocation dictates that the number of lower income, middle income, and upper income residents selected by the scientist be 108 , 38 , and 54 , respectively. Thus the scientist can obtain a stratified sample of 200 residents as follows: Number the lower income residents from 1 through 4320 and use table of random numbers to randomly select 108 of the 4320 lower income residents; number the middle income residents from 1 to 1520 and use a table of random numbers to randomly select 38 of the 1520 middle income residents; number the upper income residents from 1 to 2160 and use a table of random numbers to randomly select 54 of the 2160 upper income residents. Explanation:
11)Describe the advantages and disadvantages of cluster sampling as compared with simple random sampling.
Answer:Answers will vary. Possible answer: Cluster sampling can save time when members of the population are widely scattered geographically. The disadvantage is that members of a cluster may be more homogeneous than the members of the population as a whole and may not mirror the entire population. Explanation:
12)A tax auditor has a pile of 191 tax returns of which he would like to select 17 for a special audit. Describe a method for selecting the sample which involves systematic random sampling.
Answer:Answers will vary. Possible answer: The tax auditor could number the returns 1 through 191. He could then use a random number table to select a number at random between 1 and 11. Starting with that number, he could list every 11th number until he has 17 numbers. He could then select the tax returns corresponding to the numbers listed. Explanation:
13)Which method of sampling is easier: simple random sampling or systematic random sampling?
Answer:Systematic random sampling Explanation:
Use the random number table in Appendix A to obtain the required list of random numbers. 14)A magazine is awarding a cash prize for 10 winners in its competition. 470 of the contestants have answered all the competition questions correctly. The magazine will pick the 10 winners at random from among these 470 contestants. Construct a list of 10 random numbers between 1 and 470 that can be used in obtaining the required simple random sample. Use the random number table and use as your starting point the digits 270 in row 12, columns 5 - 7.
Answer:270, 455, 415, 151, 310, 85, 105, 378, 84, 129 Explanation:
Provide an appropriate response. 15)The effects of global warming on the planet have received increased national attention in recent years. But how many U.S. adults would be willing to change certain personal behaviors in order to help reverse the effects of global warming? A major pollster conducted a telephone poll of 1060 U.S. adults to determine the answer to the following questions: (1) Is public transportation a viable option for you? (2) If not, do you own a hybrid vehicle or one that gets more than an overall average of 30 miles per gallon? (3) If not, would you be willing to purchase a hybrid vehicle within the five years? Respondents were also asked questions about age, sex, race, education, region, and household income to ensure that results represented a cross section of U.S. adults. i) What kind of sampling design was used in this survey? Explain your answer. ii) If 86 % of the respondents answered the first question in the negative, what was the approximate sample size for the second question? iii) If 71 % of those responding to the second question answered "no," what was the approximate size for the third question?
Answer:i) This is a poll taken by calling randomly selected U.S. adults. Thus, the sampling design appears to be simple random sampling, although it is possible that a more complex, multi-stage design was used to ensure that various political, educational, or other types of groups were proportionately represented in the sample. ii) The approximate sample size for the second question was 86 % of 1060 , or 912. iii) The approximate sample size for the second question was 71 % of 912 , or 647. Explanation:
16)Fill in the following blanks: The two major types of statistics are ______________ statistics and ___________ statistics.
Answer:descriptive and inferential Explanation:
17)Define observational study and designed experiment. 17) Answer:In an observational study, researchers simply observe and measure specific characteristics as in a sample survey. In a designed experiment researchers apply some treatment and controls and then proceed to observe its effects on the subjects and take measurements. Explanation:
18)An agricultural researcher wishes to compare the yield of four different varieties of wheat. 64 plots of land are available for an experiment. On each plot of land one of the varieties of wheat will be grown. At the end of the experiment the yield for the different varieties will be compared. 32 of the plots are at one site (site A) and the other 32 are at another site (site B). The soil at site A differs significantly from the soil at site B. If the researcher wishes to design an experiment using completely randomized design, how could the wheat varieties be assigned to the different plots?
Answer:Answers will vary. Possible answer: Randomly divide the 64 plots into four groups of 16 plots each. Randomly assign each group of plots to a different variety of wheat. Explanation:
24)Give an example of a designed experiment. In your experiment, identify the experimental units, the response variable, the factor(s), the levels of each factor, and the treatments.
Answer:Answers will vary. Explanation:
25)Define probability sampling. Identify some advantages of probability sampling. 25) Answer:Probability sampling consists of using a randomizing device such as tossing a coin or consulting a random number table to decide which members of the population will constitute the sample. Probability sampling eliminates unintentional selection bias, permits the researcher to control the chance of obtaining a non-representative sample, and guarantees that the techniques of inferential statistics can be applied. Explanation:
Use the random number table in Appendix A to obtain the required list of random numbers. 26)A market researcher is conducting a telephone poll. She has a list of 581 registered voters and wishes to interview a random sample of 12 of them. Construct a list of 12 random numbers between 1 and 581 that can be used in obtaining the required simple random sample. Use the random number table and use as your starting point the digits 432 in row 13, columns 10 - 12.
Answer:432, 452, 534, 16, 343, 242, 428, 378, 163, 182, 293, 422 Explanation:
Provide an appropriate response. 27)An education researcher wishes to assess the effectiveness of three different methods for teaching young children to read. The 380 children participating in the study are divided into three groups. The study runs for six months. The children in the first group are taught using method A, the children in the second group are taught using method B, and the children in the third group are taught using method C. At the end of the six months, the reading ability of the children in the different groups is assessed. Why might randomization be used when dividing the children into three groups?
Answer:Answers will vary. Possible answer: randomization is used in order to minimize the effects of possible confounding factors such as aptitude for reading of the children in the different groups. Randomizing helps to ensure that in each group there is a mixture of reading aptitudes. Differences in reading ability between the three groups at the end of the study can then more readily be attributed to the teaching method. Explanation:
28)In a clinical trial, each participant will receive a placebo, a low dosage of a drug, or a high dosage of the drug. The participants consist of 90 men and 90 women. The 90 men are randomly divided into three groups of 30 men each. Each group of men is randomly assigned to a different treatment (placebo, low dose, or high dose). Likewise, the 90 women are randomly divided into three groups of 30 women each. Each group of women is randomly assigned to a different treatment (placebo, low dose, or high dose). Is this a completely randomized design or a randomized block design? Explain your answer.
Answer:This is a randomized block design. Explanations will vary. Explanation:
29)An agricultural researcher wishes to compare the yield of four different varieties of wheat. 64 plots of land are available for an experiment. On each plot of land one of the varieties of wheat will be grown. At the end of the experiment the yield for the different varieties will be compared. 32 of the plots are at one site (site A) and the other 32 are at another site (site B). The soil at site A differs significantly from the soil at site B. The researcher wishes to design an experiment. In this example, why might a randomized block design, with blocking by soil type, be preferable to a completely randomized design?
Answer:Answers will vary. Possible answer: by blocking, the researcher can isolate and remove the variation in yield which is due to different soil types. It will then be easier to detect the differences in yield among the four varieties of wheat, if such differences exist. Explanation:
30)Explain the difference between an observational study and a designed experiment. 30)
Answer:Answers will vary. Possible answer: In an observational study, there is no manipulation of the variables and the researchers simply observe characteristics and take measurements. In a designed experiment, the researchers manipulate variables by imposing treatments and controls before observing characteristics and taking measurements. Explanation:
31)A researcher wishes to assess the working conditions of farm workers at farms in his district. There are 37 farms in the district which are widely scattered geographically. The researcher wishes to interview at least 300 farm workers. Describe a method for selecting a sample which involves cluster sampling. Each farm employs approximately 50 workers.
Answer:Answers will vary. Possible answer: Obtain a simple random sample of the farms as follows: Number the farms 1 to 37. Use a random number table to obtain a list of six random numbers between 1 and 37. Select the farms corresponding to those six numbers and interview all workers at each of the six farms. Explanation:
32)Define simple random sampling. Explain why this is important in design of experiments. 32)
Answer:In simple random sampling, each member of the population has an equal chance of being selected. Random sampling provides us with the best representative sample in which all groups of the population are approximately proportionately represented. Careless sampling can easily result in a biased sample which may be useless. Explanation:
33)A study was conducted to evaluate the effectiveness of a new diet pill for men. A group of 3000 men were involved in the study. Of these 3000 men, 2311 took the diet pill and 889 were given a placebo. Identify the treatments, the treatment group, and the control group.
Answer:Treatments: diet pill and placebo Treatment group: the 2311 men who took the diet pill Control group: the 889 men who took the placebo Explanation:
37)A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied by size (large or small) and color (dark or light) and whose mating calls varied by pitch (high, normal, or low). The female bullfrogs were observed to see whether they approached each of the four life-sized dummies. Identify the experimental units.
A)All of the frogs, male and female B)The male bullfrogs C)The scientist D)The female bullfrogs Answer:D Explanation: A) B) C) D)
38)An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (method A, method B, and method C). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Identify the factors.
A)Teaching method and teacher B)Score on reading test C)Method A, method B, method C D)Juliana, Felix, Sonia, and Helen Answer:A Explanation: A) B) C) D)
Provide an appropriate response. 39)An education researcher randomly selects 38 schools from one school district and interviews all the teachers at each of the 38 schools. Identify the type of sampling used in this example.
A)Simple random sampling B)Systematic random sampling C)Cluster sampling D)Stratified sampling Answer:C Explanation: A) B) C) D)
A designed experiment is described. Identify the specified element of the experiment. 40)In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. Identify the factor.
A)The participants in the experiment B)Diastolic blood pressure C)The dosage of the drug D)The experimental drug Answer:D Explanation: A) B) C) D)
41)An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are two different teachers (Juliana and Felix) and three different teaching methods (method A, method B, and method C). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Identify the treatments.
A)Method A, method B, method C B)Teaching method and teacher C)Juliana and method A, Juliana and method B, Juliana and method C, Felix and method A, Felix and method B, Felix and method C D)Juliana, Felix, Sonia, and Helen Answer:C Explanation: A) B) C) D)
42)In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. Identify the response variable.
A)The participants in the experiment B)The treatment received (placebo, low dosage, high dosage) C)Change in diastolic blood pressure D)The dosage of the drug Answer:C Explanation: A) B) C) D)
43)In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the experimental drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. Identify the treatments.
A)The experimental drug B)Diastolic blood pressure at start, diastolic blood pressure at end C)Low dosage of drug, high dosage of drug D)Placebo, low dosage of drug, high dosage of drug Answer:D Explanation: A) B) C) D)
List all possible samples from the specified population. 48)Given a group of students: Allen (A), Brenda (B), Chad (C), Dorothy (D), and Eric (E), list all of the possible samples (without replacement) of size four that can be obtained from the group.
A)A,B,C,D
B)A,B,C,D A,B,C,E A,C,D,E A,D,E,B B,C,D,E
C)A,B,C,D A,B,C,E A,C,D,E A,D,E,B
D)A,B,C,D A,B,C,E A,C,D,E A,D,E,B B,C,D,E B,C,E,A B,D,E,A
C,A,B,D C,E,D,B D,A,C,E
Answer:B Explanation: A) B) C) D)
A designed experiment is described. Identify the specified element of the experiment. 49)An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (method A, method B, and method C). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Identify the levels of the factor "teaching method".
A)Score on reading test B)Teaching method and teacher C)Juliana, Felix, Sonia, and Helen D)Method A, method B, method C Answer:D Explanation: A) B) C) D)
Provide an appropriate response. 50)True or false? In simple random sampling, each possible sample is equally likely to be the one obtained.
A)True B)False Answer:A Explanation: A) B)
A designed experiment is described. Identify the specified element of the experiment. 51)A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied by size (large or small) and color (dark or light) and whose mating calls varied by pitch (high, normal, or low). The female bullfrogs were observed to see whether they approached each of the four life-sized dummies. Identify the levels of each factor.
A)Body size has two levels: large and small. Body color has two levels: dark and light. Mating call pitch has three levels: high, normal, and low. B)Body size has three levels: large, medium, and small. Body color has three levels: dark, medium, and light. Mating call pitch has three levels: high, normal, and low. C)There are three levels: body size, body color, and mating call pitch D)Body size has three levels: large, medium, and small. Body color has three levels: dark, medium, and light. Mating call pitch has two levels: high and low. Answer:A Explanation: A) B) C) D)
Provide an appropriate response. 52)At a college there are 120 freshmen, 90 sophomores, 110 juniors, and 80 seniors. A school administrator selects a simple random sample of 12 of the freshmen, a simple random sample of 9 of the sophomores, a simple random sample of 11 of the juniors, and a simple random sample of 8 of the seniors. She then interviews all the students selected. Identify the type of sampling used in this example.
A)Simple random sampling B)Systematic random sampling C)Stratified sampling D)Cluster sampling Answer:C Explanation: A) B) C) D)
Identify the study as an observational study or a designed experiment. 53)In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received the experimental drug, the second group received a placebo, and the third group received no treatment. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. The average change in blood pressure was calculated for each of the three groups and the three averages were compared.
A)Designed experiment B)Observational study Answer:A Explanation: A) B)
A designed experiment is described. Identify the specified element of the experiment. 57)In a clinical trial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. Identify the levels of the factor.
A)Placebo, low dosage, high dosage B)High blood pressure, low blood pressure C)Diastolic blood pressure at the start, diastolic blood pressure at the end D)The experimental drug Answer:A Explanation: A) B) C) D)
Identify the study as an observational study or a designed experiment. 58)An examination of the medical records of 10 , 000 women showed that those who were short and fair skinned had a higher risk of osteoperosis.
A)Designed experiment B)Observational study Answer:B Explanation: A) B)
59)An educational researcher used school records to determine that, in one school district, 84% of children living in two-parent homes graduated high school while 75% of children living in single-parent homes graduated high school.
A)Designed experiment B)Observational study Answer:B Explanation: A) B)
List all possible samples from the specified population. 60)The members of a board of directors have the following roles:president (P),vice president (V), secretary (S),treasury (T),andfundraiser (F).Consider these board members to be a population of interest. List the 10 possible samples (without replacement) of size two from this population of five board members.
A)S,T S,F T,P T,V T,S T,F F,P F,V F,S F,T
B)P,V P,S P,T P,F V,P V,S V,T V,F S,P S,V
C)P,P P,V P,S P,T P,F V,V V,S V,T V,F S,S
D)P,V P,S P,T P,F V,S V,T V,F S,T S,F T,F
Answer:D Explanation: A) B) C) D)
Answer the question. 61)A computer network manager wants to test the reliability of some new and expensive fiber-optic Ethernet cables that computer department just received. The computer department received 7 boxes containing 10 cables each. The manager does not have the time to test every cable in each box. The manager will choose one box at random and test 2 cables chosen randomly within that box. What is the sample?
A)The one box that was chosen at random from the 7 boxes B)The 7 boxes C) 70 cables D)The 2 cables chosen for testing Answer:D Explanation: A) B) C) D)
Provide an appropriate response. 62)A newly-premiered play just ended that evening at a local theater. Theater management briefly interviews everyninthperson leaving the theater to see if that person will recommend the play at that theater to other people. Identify the type of sampling used in this example.
A)Multistage sampling B)Systematic sampling C)Stratified sampling D)Cluster sampling Answer:B Explanation: A) B) C) D)
A designed experiment is described. Identify the specified element of the experiment. 63)A herpetologist performed a study on the effects of the body type and mating call of the male bullfrog as signals of quality to mates. Four life-sized dummies of male bullfrogs and two sound recordings provided a tool for testing female response to the unfamiliar frogs whose bodies varied by size (large or small) and color (dark or light) and whose mating calls varied by pitch (high, normal, or low). The female bullfrogs were observed to see whether they approached each of the four life-sized dummies. Identify the response variable.
A)Whether or not (yes or no) the female frogs approached a male dummy B)The four life-sized dummy male bullfrogs C)Whether or not the male frogs were large and light-colored D)Large and small; dark and light; call and no call Answer:A Explanation: A) B) C) D)
A designed experiment is described. Identify the specified element of the experiment. 67)An education researcher was interested in examining the effect of the teaching method and the effect of the particular teacher on students' scores on a reading test. In a study, there are four different teachers (Juliana, Felix, Sonia, and Helen) and three different teaching methods (method A, method B, and method C). The number of students participating in the study is 258. Students are randomly assigned to a teaching method and teacher. Identify the response variable.
A)Teaching method B)Teacher C)Method A, method B, method C D)Score on reading test Answer:D Explanation: A) B) C) D)
Identify the study as an observational study or a designed experiment. 68)At one hospital in 1992, 674 women were diagnosed with breast cancer. Five years later, 88% of the Caucasian women and 83% of the African American women were still alive.
A)Designed experiment B)Observational study Answer:B Explanation: A) B)
Provide an appropriate response. 69)The members of a board of directors have the following roles:president (P),vice president (V), secretary (S),treasury (T),andfundraiser (F).Consider these board members to be a population of interest. The possible samples (without replacement) of size two that can be obtained from these five board members are as follows.
P,V P,S P,T P,F V,S V,T V,F S,T S,F T,F
If a simple random sampling method is used to obtain a sample of two of the board members, what are the chances of selecting the secretary and the treasurer?
A)^15 B)^25 C) 201 D) 101
Answer:D Explanation: A) B) C) D)
List all possible samples from the specified population. 70)The finalists in an essay competition areLisa (L),Melina (M),Ben (B),Danny (D),Eric (E),and Joan (J).Consider these finalists to be a population of interest. List the 15 possible samples (without replacement) of size two from this population of six finalists.
A)D,D D,E D,J E,L E,M E,B E,D E,E E,J J,L J,M J,B J,D J,E J,J
B)L,M L,B L,D L,E L,J M,B M,D
M,E M,J B,D B,E B,J D,E D,J E,J
C)L,L L,M L,B L,D L,E L,J M,M M,B
M,D M,E M,J B,B B,D B,E B,J
D)L,L L,M L,B L,D L,E L,J M,L M,M
M,B M,D M,E M,J B,L B,M B,B
Answer:B Explanation: A) B) C) D)
Provide an appropriate response. 71)The finalists in an essay competition areLisa (L),Melina (M),Ben (B),Danny (D),Eric (E),and Joan (J).Consider these finalists to be a population of interest. The possible samples (without replacement) of size two that can be obtained from this population of six finalists are as follows.
L,M L,B L,D L,E L,J M,B M,D M,E M,J B,D B,E B,J D,E D,J E,J
If a simple random sampling method is used to obtain a sample of two of the finalists, what are the chances of selecting Lisa and Danny?
A) 152 B)^16 C)^13 D) 151
Answer:D Explanation: A) B) C) D)
Answer the question. 72)George, a network engineer, ordered 500 CAT 5e Ethernet cables for use at his company's network. After receiving these cables, he decided to randomly test 150 of these cables before using them. He was alarmed to find out that 92 % of these cables failed completely. He returned the entire lot to the manufacturer. When he tested the cables, what was George's sample?
A) 500 cables B) 460 cables C) 150 cables D) 138 cables Answer:C Explanation: A) B) C) D)
