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STAT 2025-2026 Final Exam Study Set –
OSU Newest Questions & Correct
Answers. Graded A
A Binomial random variable is right skewed if the probability of success on one trial is .9. – ANS false A cigar factory produces thick cigars that have a mean diameter of 14 centimeters. Since the cigars are hand-rolled, they are not all exactly the same diameter. The standard deviation of the cigar diameter is 1. centimeters. The cigar factory is interested in maintaining a reasonably consistent diameter, so the factory takes repeated samples of 49 cigars chosen randomly each day. Only 1.5% of the time will the sample mean cigar diameter be less than how many centimeters? - ANS13.566cm A cigar factory produces thick cigars that have a mean diameter of 14 centimeters. Since the cigars are hand-rolled, they are not all exactly the same diameter. The standard deviation of the cigar diameter is 1. centimeters. The cigar factory is interested in maintaining a reasonably consistent diameter, so the factory takes repeated samples of 49 cigars chosen randomly each day. Thirty-three percent of the cigar diameter sample means that result from the above sampling situation will be more than what value? - ANS14.088cm A cigar factory produces thick cigars that have a mean diameter of 14 centimeters. Since the cigars are hand-rolled, they are not all the same
diameter. The standard deviation of the cigar diameter is 1.4 centimeters. The cigar factory is interested in maintaining a reasonably consistent diameter, so the factory takes repeated samples of 49 cigars chosen randomly each day. What is the probability that the cigar diameter sample mean which results from the above situation will be between 13.55 and 14.61 centimeters? - ANS0. A coach was interested in estimating the average resting heart rate of distance runners. He took a random sample of 4 distance runners and found a sample mean of 42 beats per minute with a sample standard deviation of 6 beats per minute. Assume it is reasonable that the sample is from a normally distributed population. Suppose this coach is checking whether the data indicate that the runner population mean heart rate is greater than 38. Consider a hypothesis test with alpha = 0.05. What is the alternative hypothesis? - ANSμ > 38 A coach was interested in estimating the average resting heart rate of distance runners. He took a random sample of 4 distance runners and found a sample mean of 42 beats per minute with a sample standard deviation of 6 beats per minute. Assume it is reasonable that the sample is from a normally distributed population. Suppose this coach is checking whether the data indicate that the runner population mean heart rate is greater than 38. Consider a hypothesis test with alpha = 0.05. What is the conclusion in the hypotheisis test? - ANSdata do not support the alternative A coach was interested in estimating the average resting heart rate of distance runners. He took a random sample of 4 distance runners and
tested in a two-tail hypothesis test with the same significance level. - ANStrue A continuous random variable has probability on intervals of values, but no probability on specific values. - ANStrue A continuous random variable has probability that described with a probability density function and the area under the curve indicates the probability for a specific interval of values. - ANStrue A continuous random variable is a variable that can be described as the number of success outcomes in n independent trials. - ANSfalse A discrete random variable has probability of 0.10 on each of the values 10, 20, 30, and 40. The other two values of the variable are 50 and 60, each having equal probability. What is the expected value of this discrete random variable? - ANS A discrete random variable has probability on intervals of values but has no probability on specific values. - ANSfalse A discrete random variable has probability on intervals of values, but no probability on specific values. - ANSfalse A dried fruit company in California, bellaviva.com, receives an average of 0.6 online orders per minute. What is the probability that in a randomly
chosen minute that website will receive at least one online order? - ANS0. A dried fruit company in California, bellaviva.com, receives an average of 0.8 online orders per minute. What is the probability that in a randomly chosen minute that website will receive at least one online order? - ANS0. A field medical device injects patients with a specific amount of fluid, but the process has a slight amount of variation. One setting on the device has a mean injection amount of 1.2ml with a standard deviation of 0.1ml. Assume that samples of 100 observations were repeatedly recorded from this setting on the field medical injection device. Consider the set of all sample means that would result from the repeated sampling process. If the average over 100 observations exceeds 1.232, that indicates that the field medical device may be delivering toxic levels of the fluid to patients. What is the probability that this risk may occur even if the device has a mean injection amount of 1.2ml? - ANS0. A field medical device injects patients with a specific amount of fluid, but the process has a slight amount of variation. One setting on the device has a mean injection amount of 1.2ml with a standard deviation of 0.1ml. Assume that samples of 100 observations were repeatedly recorded from this setting on the field medical injection device. Consider the set of all sample means that would result from the repeated sampling process. The sample mean of 100 observations from this field medical injection device will be less than what value 1.7% of the time? - ANS1.
What percent of the time is the mean of 100 injections greater than 2.4557ml? - ANS0.2% A gambler has the probability 0.42 to win a game. If this game is played seven times what is the probability that the gambler will win fewer than 2 times? - ANS0. A lawyer estimates that 36% of the cases in which she represented the defendant were won. If the lawyer is presently representing 10 defendants in different cases, what is the probability that 5 of the cases will be won? - ANS0. A loan officer compares the interest rates for 48-month fixed-rate auto loans and 48-month variable-rate auto loans. Two independent, random samples of auto loan rates are selected. A sample of eight 48-month fixed-rate auto loans had the following loan rates: 12.29% 11.75% 9.50% 8.99% 9.25% 10.99% 9.40% 11.55% while a sample of five 48-month variable-rate auto loans had loan rates as follows: 8.59% 9.75% 7.99% 9.50% 8.29% What is the alternative hypothesis if the question is whether the data supports the conclusion that the mean of the population of loan percentages for fixed rate loans is greater than the mean of the population of loan percentages for variable rate loans? - ANSM1-M2>
A loan officer compares the interest rates for 48-month fixed-rate auto loans and 48-month variable-rate auto loans. Two independent, random samples of auto loan rates are selected. A sample of eight 48-month fixed-rate auto loans had the following loan rates: 12.29% 11.75% 9.50% 8.99% 9.25% 10.99% 9.40% 11.55% while a sample of five 48-month variable-rate auto loans had loan rates as follows: 8.59% 9.75% 7.99% 9.50% 8.29% What is the value of the test statistic to test whether the mean of the population of fixed rate loan percentages is equal to the mean of the population of variable rate loan percentages? - ANS2. A loan officer compares the interest rates for 48-month fixed-rate auto loans and 48-month variable-rate auto loans. Two independent, random samples of auto loan rates are selected. The resulting data are: Fixed-rate:8.9% 7.8% 7.6% 9.1% 6.8% 8.2% 7.6% Variable-rate:6.2% 4.5% 5.5% 4.4% 6.1% 6.9% What is the point estimate for the mean of the population of variable-rate loan percentage? - ANS5.
A point estimate is a single number calculated from observed data that is used to estimate a _________. - ANSpopulation parameter A probability density function is a function that indicates how much of the mass of the unit probability is assigned to each value of a discrete random variable. - ANSfalse A random sample of eight roadrunners was collected in the Oklahoma panhandle and the heights in inches of each of the road runners are: 12.6, 15.2, 14.8, 13.1, 12.9, 14.7, 14.2, 13.2What is a numerical value for the standard deviation of the sample of road runner heights? - ANS1. A random sample of eight roadrunners was collected in the Oklahoma panhandle and the heights in inches of each of the road runners are: 12.6, 15.2, 14.8, 13.1, 12.9, 14.7, 14.2, 13.2What is the numerical value of the square of the sum for the sample of roadrunner heights? - ANS12,254. A random sample of eight roadrunners was collected in the Oklahoma panhandle and the heights in inches of each of the road runners are:12.6, 15.2, 14.8, 13.1, 12.9, 14.7, 14.2, 13.2What is the numerical value of the mean for the sample of roadrunner heights? - ANS13. A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean
IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What are the rejection region critical values? - ANS(-2.131, 2.131) A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What is the alternative hypothesis? - ANSμ ≠ 103 A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What is the conclusion in the hypothesis test? - ANSthere is not sufficient evidence to claim the mean is different from 103 A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What
A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What is the observed test statistic value? - ANS-1. A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What is the p-value of the hypothesis test - ANS0. A researcher is interested in estimating the average IQ in a population. She took a random sample of 16 subjects and found a sample mean of 100 with a sample standard deviation of 10. Assume it is reasonable that the sample was drawn from a normally distributed population. Suppose the researcher is interested in whether the data support the idea that the population mean IQ is different than 103. Consider a hypothesis test with alpha = 0.05. What is the p-value of the hypothesis test? - ANS0. A researcher was interested in estimating the mean age for females in a population. A random sample of 25 females was taken. The resulting sample mean was 45 years and the sample standard deviation was 5
years. Assume it is reasonable that the sample is from a normally distributed population. The researcher is interested in whether the data support the idea that the female population mean age is less than 48. Consider a hypothesis test with alpha = 0.05. What is the alternative hypothesis? - ANSμ < 48 A researcher was interested in estimating the mean age for females in a population. A random sample of 25 females was taken. The resulting sample mean was 45 years and the sample standard deviation was 5 years. Assume it is reasonable that the sample is from a normally distributed population. The researcher is interested in whether the data support the idea that the female population mean age is less than 48. Consider a hypothesis test with alpha = 0.05. What is the conclusion of the hypothesis test? - ANSdata support the alternative hypothesis A researcher was interested in estimating the mean age for females in a population. A random sample of 25 females was taken. The resulting sample mean was 45 years and the sample standard deviation was 5 years. Assume it is reasonable that the sample is from a normally distributed population. The researcher is interested in whether the data support the idea that the female population mean age is less than 48. Consider a hypothesis test with alpha = 0.05. What is the decision in the hypothesis test? - ANSReject H(o) A researcher was interested in estimating the mean age for females in a population. A random sample of 25 females was taken. The resulting sample mean was 45 years and the sample standard deviation was 5
For budgeting purposes, the company needs to estimate next month's employee reimbursement expenses. How much money should the company budget if they want the probability of exceeding the budgeted amount to be only 0.30? - ANS$6, A small company in Altus, Oklahoma reimburses their employees for expenses each month. The amount of employee reimbursements each month is uniformly distributed between the values of $4,000 and $8,000. What is the probability of employee reimbursements exceeding $7,500 next month? - ANS0. A star basketball player at Oklahoma State University hits 84% of his free throw attempts. If this player is fouled while shooting a three-point basket he would be allowed three free throw attempts. When this player is allowed three free throw attempts, what is the probability that he will hit at least two of them? - ANS0. A tennis player was interested in estimating the average weight of tennis racquets used by professional players. He took a random sample of 4 tennis racquets from professional players and calculated a sample mean of 300 grams with a sample standard deviation of 1 gram. Assume the sample is from a normally distributed population. Do the data indicate that the population mean weight of tennis racquets used by professional players is greater than 298 grams. Consider a hypothesis test with alpha = 0.05.What is the alternative hypothesis? - ANSμ > 298
A tennis player was interested in estimating the average weight of tennis racquets used by professional players. He took a random sample of 4 tennis racquets from professional players and calculated a sample mean of 300 grams with a sample standard deviation of 1 gram. Assume the sample is from a normally distributed population. Do the data indicate that the population mean weight of tennis racquets used by professional players is greater than 298 grams. Consider a hypothesis test with alpha = 0.05.What is the decision in the hypothesis test? - ANSReject H(o) A tennis player was interested in estimating the average weight of tennis racquets used by professional players. He took a random sample of 4 tennis racquets from professional players and calculated a sample mean of 300 grams with a sample standard deviation of 1 gram. Assume the sample is from a normally distributed population. Do the data indicate that the population mean weight of tennis racquets used by professional players is greater than 298 grams. Consider a hypothesis test with alpha = 0.05.What is the null hypothesis - ANSμ = 298 A tennis player was interested in estimating the average weight of tennis racquets used by professional players. He took a random sample of 4 tennis racquets from professional players and calculated a sample mean of 300 grams with a sample standard deviation of 1 gram. Assume the sample is from a normally distributed population. Do the data indicate that the population mean weight of tennis racquets used by professional players is greater than 298 grams. Consider a hypothesis test with alpha = 0.05.What is the null hypothesis? - ANSμ = 298
As the sample size increases the standard errors of the point estimates also increase. - ANStrue Assume 100 observations were randomly drawn from a population of investment returns with a mean of 1,650 dollars and a standard deviation of 50 dollars. Only 0.28% (or 0.0028) of the sample means that result from this sampling situation will be less than what value? - ANS1,636.148cm Assume 100 observations were randomly drawn from a population of investment returns with a mean of 1,650 dollars and a standard deviation of 50 dollars. What is the probability that the sample mean that results from this situation will be between 1,647 and 1,657 dollars? - ANS0. Assume 400 observations were randomly drawn from a population of investment returns with a mean of 65 dollars and a standard deviation of 50 dollars. What is the probability that the sample mean that results from the above situation will be between 63.75 and 70.5? - ANS0. Assume a uniform discrete random variable has 10 possible values. What would be the cumulative probability on four of the possible 10 values? - ANS0. Assume a uniform discrete random variable has 8 possible values. What would be the cumulative probability on three of the possible 8 values? - ANS0.
Assume an unfair die has 0.75 probability on the value 6 and the remaining probability is divided equally to the other 5 values on the die. What is the probability on the value 5? - ANS0. Assume that 80% of the new oil wells in Oklahoma are horizontal wells. Further assume that 76% of all the new oil wells in the state have more than more than 10 barrels per day initial production. Of the new horizontal wells, 90% result in more than 10 barrels of oil per day in initial production. What is the probability that a new oil well is a horizontal well or will result in more than 10 barrels of oil per day in initial production? - ANS0. Assume that a discrete random variable has five possible values (1, 2, 3, 5,
- and each value has the same probability. What is the variance of such a random variable? - ANS25. Assume that a discrete random variable has five possible values, 10, 12, 14, 16, and 28. If the probability on each of the first two values, 10 and 12, is 0.125 and the remaining probability is divided equally for the other three values of the variable, 14, 16, and 28, then what is the expected value of such a random variable? - ANS17. Assume that a discrete random variable has four possible values, 15, 20, 25, and 30. If there is 0.30 probability on each of the two values that end in 5, the values 15 and 25, and the remaining probability is divided equally for the other two values of the variable, 20 and 30, then what is the probability that such a random variable is at least the value of 25? - ANS0.
