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Straighterline Business Stats Final exam with 100% correct answers(graded A+).docx
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The main purpose of descriptive statistics is to - answer Summarize data in a useful and informative manner Which word is NOT part of the definition of descriptive statistics? - answer Predicting A marketing class of 50 students evaluated the instructor using the following scale: superior, good, average, poor, and inferior. The descriptive
summary showed the following survey results: 2% superior, 8% good, 45% average, 45% poor, and 0% inferior. - answer c. Most students rated the instructor as poor or average. What type of variable is the number of robberies reported in your city? - answer Quantitative The Nielsen Ratings break down the number of people watching a particular television show by age. What level of measurement is age? - answer Ratio What level of measurement is a person's "favorite sport"? - answer Nominal The final rankings of the top 20 NCAA college basketball teams are an example of which level of measurement? - answer Ordinal What level of measurement is the Centigrade temperature scale? - answer Interval A survey includes a question regarding marital status that has the following responses: single, married, divorced, separated, or widowed. What is
Assume a student received the following grades for the semester: History, B; Statistics, A; Spanish, C; and English, C. History and English are 5 credit- hour courses, Statistics a 4 credit-hour course, and Spanish a 3 credit-hour course. If 4 grade points are assigned for an A, 3 for a B, and 2 for a C, what is the weighted mean grade for the semester? - answer 2. A disadvantage of using an arithmetic mean to summarize a set of data is that __________. - answer It can be biased by one or two extremely small or large values A survey item asked students to indicate their class in college: freshman, sophomore, junior, or senior. Which measure(s) of central location would be appropriate for the data generated by that questionnaire item? - answer Mode and median The times (in minutes) that several underwriters took to review applications for similar insurance coverage are 50, 230, 52, and 57. What is the median length of time required to review an application? - answer 54.
For the most recent seven years, the U.S. Department of Education reported the following number of bachelor's degrees awarded in computer science: 4,033; 5,652; 6,407; 7,201; 8,719; 11,154; 15,121. What is the annual arithmetic mean number of degrees awarded? - answer About 8, Which of the following measures of dispersion are based on deviations from the mean? - answer All apply From the easiest to the hardest "ease of interpretation," rank the measures of dispersion. - answer Range, mean deviation, variance The weights of a sample of crates ready for shipment to Moscow, Russia are (in kilograms): 103, 97, 101, 106, and 103. What is the mean deviation? - answer 2.4 kg A sample of assistant professors on the business faculty at state-supported institutions in Ohio revealed the mean income to be $72,000 for nine months, with a standard deviation of $3,000. Using Chebyshev's Theorem, what proportion of the faculty earns more than $66,000, but less than $78,000? - answer At least 75%
To locate the percentile for a given observation in a data set, the data must be ___________. - answer Sorted and listed from the minimum to the maximum values The test scores for a class of 147 students are computed. What is the location of the test score associated with the third quartile? - answer 111 In a distribution, the second quartile corresponds with the __________. - answer Median A dot plot shows ____________. - answer The general shape of a distribution The range of the coefficient of skewness is ____________. - answer Both positive and negative values A sample of experienced typists revealed that their mean typing speed is 87 words per minute and the median typing speed is 73 words per minute. The standard deviation of typing speed is 16.9 words per minute. What is the Pearson coefficient of skewness? - answer +2.
If the coefficient of skewness is equal to zero, the shape of the distribution is __________. - answer Symmetric A large oil company is studying the number of gallons of gasoline purchased per customer at self- service pumps. The mean number of gallons is 10.0, with a standard deviation of 3.0 gallons. The median is 10.75 gallons. What is Pearson's coefficient of skewness in this instance? - answer -
In a contingency table, we describe the relationship between ________. - answer Two variables measured at the ordinal or nominal level The first card selected from a standard 52-card deck was a king. If it is NOT returned to the deck, what is the probability that a king will be drawn on the second selection? - answer 3/51 or 0. There are 10 AAA batteries in a box and 3 are defective. Two batteries are selected without replacement. What is the probability of selecting a defective battery followed by another defective battery? - answer 1/15 or about 0.
Supervisors A 120 Maint B 50 Production C 1460 Management D 302 Secretarial E 68 What is the probability that the first person selected is classified as a maintenance employee? - answer 0. The probability of an event that is affected by one or more other events is called a ___________. - answer Conditional probability A study of interior designers' opinions with respect to the most desirable primary color for executive offices showed that: Primary Color # of Opinions Red 92 Orange 86 Yellow 46 Green 91 Blue 37 Indigo 46
Violate 2 What is the probability that a designer does not prefer blue? - answer 0. The numbers 0 through 9 are used in code groups of four to identify an item of clothing. Code 1083 might identify a blue blouse, size medium. The code group 2031 might identify a pair of pants, size 18, and so on. Repetitions of numbers are not permitted—in other words, the same number cannot be used more than once in a total sequence. As examples, 2256, 2562, or 5559 would not be permitted. How many different code groups can be designed? - answer 5, You have the assignment of designing color codes for different parts. Three colors are used to code on each part. Once a combination of three colors is used—such as green, yellow, and red—these three colors cannot be rearranged to use as a code for another part. If there are 35 combinations, how many colors were available? - answer 7 A developer of a new subdivision wants to build homes that are all different. There are three different interior plans that can be combined with any of five different home exteriors. How many different homes can be built? - answer 15
counted 3,500 borers in the 5,000 ears. What is the probability that an ear of corn selected at random will contain no borers? - answer 0. In a Poisson distribution, the variance is equal to ___________. - answer nπ A statistics professor receives an average of five e- mail messages per day from students. Assume the number of messages approximates a Poisson distribution. What is the probability that on a randomly selected day she will have no messages?
Which of the following is NOT a characteristic of a binomial probability distribution? - answer The number of trials is limited to two. A tennis match requires that a player win three of five sets to win the match. If a player wins the first two sets, what is the probability that the player wins the match, assuming that each player is equally likely to win each set? - answer 0. A company is studying the number of monthly absences among its 125 employees. The following probability distribution shows the likelihood that people were absent 0, 1, 2, 3, 4, or 5 days last month.
0 0. 1 0. 2 0. 3 0. 4 0. 5 0. What is the variance of the number of days absent?
Which of the following is a characteristic of the normal probability distribution? - answer It's bell- shaped. The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the probability of a weight between 415 pounds and the mean of 400 pounds? - answer 0. In an illustration of a normal probability distribution, a shaded area represents _______. - answer A probability A cola-dispensing machine is set to dispense a mean of 2.02 liters into a container labeled 2 liters. Actual quantities dispensed vary and the amounts are normally distributed with a standard deviation of 0.015 liters. What is the probability a container will have less than 2 liters? - answer 0. The wildlife department has been feeding a special food to rainbow trout fingerlings in a pond. Based on a large number of observations, the distribution of trout weights is normally distributed with a mean of 402.7 grams and a standard deviation 8. grams. What is the probability that the mean weight for a sample of 40 trout exceeds 405. grams? - answer 0.
Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The mean tread wear was 50, miles, with a standard deviation of 3,500 miles. What is the best estimate of the average tread life in miles for the entire population of these tires? - answer 50, When testing the safety of cars using crash tests, a sample of one or two cars is used because ___________. - answer Cars are destroyed The tread life of tires mounted on light-duty trucks follows the normal probability distribution with a mean of 60,000 miles and a standard deviation of 4,000 miles. Suppose we select a sample of 40 tires and use a simulator to determine the tread life. What is the standard error of the mean? - answer 632. The size of the sampling error is ________. - answer Inversely related to the sample size—in other words, the larger the sample size, the smaller the sampling error The Office of Student Services at a large western state university maintains information on the
mean of this sample is between 95 and 105? - answer 0. Mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The results showed that the mean tread life was 50,000 miles, with a standard deviation of 3,500 miles. What is the best estimate of the mean tread life in miles for the entire population of these tires? - answer 50, A university surveyed recent graduates of the English Department for their starting salaries. Four hundred graduates returned the survey. The average salary was $25,000. The population standard deviation is $2,500. A 95% confidence interval is constructed. What does the confidence interval mean? - answer The likelihood that any confidence interval based on a sample of 400 graduates will contain the population mean is 0. What is the interpretation of a 96% confidence level? - answer Approximately 96 out of 100 such intervals would include the true value of the population parameter. Suppose 1,600 of 2,000 registered voters sampled said they planned to vote for the Republican candidate for president. Using the 0.95 degree of
confidence, what is the interval estimate for the population proportion (to the nearest 10th of a percent)? - answer 78.2% to 81.8% Which of the following is a point estimate for the population mean (μ)? - answer x̄ A survey of 50 retail stores revealed that the average price of a microwave was $375, with a sample standard deviation of $20. Assuming the population is normally distributed, what is the 95% confidence interval to estimate the true cost of the microwave? - answer $369.31 to $380. If 95% and 98% confidence intervals were developed to estimate the true cost of an MP player with a known population standard deviation, what differences would they have? - answer The z statistics would be different. A survey of 25 grocery stores revealed that the average price of a gallon of milk was $2.98, with a standard error of $0.10. What is the 98% confidence interval to estimate the true cost of a gallon of milk? - answer $2.73 to $3.
