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- 1. Multiple Choice
The heights of adult women are approximately normally distributed about a mean of 65 inches with a standard deviation of 2 inches. If Rachael is at the 99th percentile in height for adult women, then her height, in inches, is closest to
60
62
68
70
74
- 2. Multiple Choice
Joe and Matthew plan to visit a bookstore. Based on their previous visits to this bookstore, the probability distributions of the number of books they will buy are given below.
Assuming that Joe and Matthew make their decisions independently, what is the probability that they will purchase no books on the visit to the bookstore?
0.0625
0.1250
0.1875
0.2500
0.7500
- 3. Multiple Choice
A survey of 57 students was conducted to determine whether or not they held jobs outside of school. The two-way table above shows the numbers of students by employment status (job, no job) and class (juniors, seniors). Which of the following best describes the relationship between employment status and class?
There appears to be no association, since the same number of juniors and seniors have jobs.
There appears to be no association, since close to half of the students have jobs.
There appears to be no association, since there are more seniors than juniors in the survey.
There appears to be no association, since the proportion of juniors having jobs is much larger than the proportion of seniors having jobs.
A measure of association cannot be determined from these data.
- 4. Multiple Choice
Which of the following is the best estimate of the standard deviation of the distribution show in the figure?
5
10
30
50
60
- 5. Multiple Choice
Ten students were randomly selected from a high school to take part in a program designed to raise their reading comprehension. Each student took a test before and after completing the program. The mean of the differences between the score after the program and the score before the program is 16. It was decided that all students in the school would take part in this program during the next school year. Let µA denote the mean score after the program and µB denote the mean score before the program for all students in the school. The 95 percent confidence interval estimate of the true mean difference for all students is (9, 23). Which of the following statements is a correct interpretation of this confidence interval?
µA > µB with probability 0.95.
µA < µB with probability 0.95.
µA is around 23 and µB is around 9.
For any µA and µB with (µA - µB) ≥ 14, the sample result is quite likely.
For any µA and µB with 9 < (µA - µB) < 23, the sample result is quite likely.
- 6. Multiple Choice
Gina's doctor told her the standardized score (z-score) for her systolic blood pressure, as compared to the blood pressure of other women her age, is 1.50. Which of the following is the best interpretation of this standardized score?
Gina's systolic blood pressure is 150.
Gina's systolic blood pressure is 1.50 standard deviations above the average systolic blood pressure of women her age.
Gina's systolic blood pressure is 1.50 above the average systolic blood pressure of women her age.
Gina's systolic blood pressure is 1.50 times the average systolic blood pressure for women her age.
Only 1.5% of women Gina's age have a higher systolic blood pressure than she does.
- 7. Multiple Choice
The Physicians' Health Study, a large medical experiment involving 22,000 male physicians, attempted to determine whether aspirin could help prevent heart attacks. In this study, one group of about 11,000 physicians took an aspirin every other day, while a control group took a placebo. After several years, it was determined that the physicians in our control group. Which of the following statements explains why it would not be appropriate to say that everyone should take an aspirin every other day?
I. The study included only physicians, and different results may occur in individuals in other occupations.
II. The study included only males and there may be different results for females.
III. Although taking aspirin may be helpful in preventing heart attacks, it may be harmful to some other aspects of health.
I only
II only
III only
II and III only
I, II, and III
- 8. Multiple Choice
Every Thursday, Matt and Dave's Video Venture has "roll-the-dice" day. A customer may choose to roll two fair dice and rent a second movie for an amount (in cents) equal to the numbers uppermost on the dice, with the larger number first. For example, if the customer rolls a two and a four, a second movie may be rented for $0.42. If a two and a two are rolled, a second movie may be rented for $0.22. Let X represent the amount paid for a second movie on roll-the-dice day. The expected value of X is $0.47 and the standard deviation of X is $0.15.
If a customer rolls the dice and rents a second movie every Thursday for 20 consecutive weeks, what is the total amount that the customer would expect to pay for these second movies?
$0.45
$0.47
$0.67
$3.00
$9.40
- 9. Multiple Choice
Every Thursday, Matt and Dave's Video Venture has "roll-the-dice" day. A customer may choose to roll two fair dice and rent a second movie for an amount (in cents) equal to the numbers uppermost on the dice, with the larger number first. For example, if the customer rolls a two and a four, a second movie may be rented for $0.42. If a two and a two are rolled, a second movie may be rented for $0.22. Let X represent the amount paid for a second movie on roll-the-dice day. The expected value of X is $0.47 and the standard deviation of X is $0.15.
If a customer rolls the dice and rents a second movie every Thursday for 30 consecutive weeks, what is the approximate probability that the total amount paid for these second movies will exceed $15.00?
0
0.09
0.14
0.86
0.91
- 10. Multiple Choice
A company wanted to determine the health care costs of its employees. A sample of 25 employees were interviewed and their medical expenses for the previous year were determined. Later the company discovered that the highest medical expense in the sample was mistakenly recorded as 10 times the actual amount. However, after correcting the error, the corrected amount was still greater than equal to any other medical expense in the sample. Which of the following sample statistics must have remained the same after the correction was made?
Mean
Median
Mode
Range
Variance
- 11. Multiple Choice
The back-to-back stem-and-leaf plot below gives the percentage of students who dropped out of school at each of the 49 high schools in a large metropolitan school district.
Which of the following statements is NOT justified by these data?
The drop-out rate decreased in each of the 49 high schools between the 1989-1990 and 1992-1993 school years.
For the school years shown, most students in the 49 high schools did not drop out of high school.
In general, drop-out rates decreased between the 1989-1990 and 1992-1993 school years.
The median drop-out rate of the 49 high schools decreased between the 1989-1990 and 1992-1993 school years.
The spread between the schools with the lowest drop-out rates and those with the highest drop-out rates did not change much between the 1989-1990 and 1992-1993 school years.
- 12. Multiple Choice
Circuit boards are assembled by selecting 4 computer chips at random from a large batch of chips. In this batch of chips, 90 percent of the chips are acceptable. Let X denote the number of acceptable chips out of a sample of 4 chips from this batch. What is the least probable value of X?
0
1
2
3
4
- 13. Multiple Choice
A random sample of the costs of repair jobs at a large muffler repair shop produces a mean of $127.95 and a standard deviation of $24.03. If the size of this sample is 40, which of the following is an approximate 90 percent confidence interval for the average cost of a repair at this repair shop?
$127.95 ± $4.87
$127.95 ± $6.25
$127.95 ± $7.45
$127.95 ± $30.81
$127.95 ± $39.53
- 14. Multiple Choice
At a college the scores on the chemistry final exam are approximately normally distributed, with a mean of 75 and a standard deviation of 12. The scores on the calculus final are also approximately normally distributed, with a mean of 80 and a standard deviation of 8. A student scored 81 on the chemistry final and 84 on the calculus final. Relative to the students in each respective class, in which subject did this student do better?
The student did better in chemistry.
The student did better in calculus.
The student did equally well in each course.
There is no basis for comparison, since the subjects are different from each other and are in different departments.
There is not enough information for comparison, because the number of students in each class is not known.
- 15. Multiple Choice
A fair coin is flipped 10 times and the number of heads is counted. This procedure of 10 coin flips is repeated 100 times and the results are placed in a frequency table. Which of the frequency tables below is most likely to contain the results from these 100 trials?
- 16. Multiple Choice
The student government at a high school wants to conduct a survey of student opinion. It wants to begin with a simple random sample of 60 students. Which of the following survey methods will produce a simple random sample?
Survey the first 60 students to arrive at school in the morning.
Survey every 10th student entering the school library until 60 students are surveyed.
Use random numbers to choose 15 each of first-year, second-year, third-year, and fourth-year students.
Number the cafeteria seats. Use a table of random numbers to choose seats and interview the students until 60 have been interviewed.
Number the students in the official school roster. Use a table of random numbers to choose 60 students from this roster for the survey.
- 17. Multiple Choice
There is a linear relationship between the number of chirps made by the striped ground cricket and the air temperature. A least squares fit of some data collected by a biologist gives the model
y = 25.2 + 3.3x 9 < x < 25,
where x is the number of chirps per minute and y is the estimated temperature in degrees Fahrenheit. What is the estimated increase in temperature that corresponds to an increase of 5 chirps per minute?
3.3°F
16.5°F
25.2°F
28.5°F
41.7°F
- 18. Multiple Choice
In a test of the null hypothesis H0: µ = 10 against the alternative hypothesis Ha: µ > 10, a sample from a normal population produces a mean of 13.4. The z-score for the sample is 2.12 and the p-value is 0.017. Based on these statistics, which of the following conclusions could be drawn?
There is reason to conclude that µ > 10.
Due to random fluctuation, 48.3 percent of the time a sample produces a mean larger than 10.
1.7 percent of the time, rejecting the alternative hypothesis is in error.
1.7 percent of the time, the mean is above 10.
1.7 percent of the time, the mean is below 10.
- 19. Multiple Choice
For which of the following distributions is the mean greater than the median?
- 20. Multiple Choice
The equation of the least squares regression line for the points on the scatterplot above is y = 1.3 + 0.73x. What is the residual for the point (4, 7)?
2.78
3.00
4.00
4.22
7.00
- 21. Multiple Choice
The distribution of the weights of loaves of bread from a certain bakery follows approximately a normal distribution. Based on a very large sample, it was found that 10 percent of the loaves weighed less than 15.34 ounces, and 20 percent of the loaves weighed more than 16.31 ounces. What are the mean and standard deviation of the distribution of the weights of the loaves of bread?
µ = 15.82, σ = 0.48
µ = 15.82, σ = 0.69
µ = 15.87, σ = 0.50
µ = 15.93, σ = 0.46
µ = 16.00, σ = 0.50
- 22. Multiple Choice
A 95 percent confidence interval of the form p̂ ± E will be used to obtain an estimate for an unknown population proportion p. If p̂ is the sample proportion and E is the margin of error, which of the following is the smallest sample size that will guarantee a margin of error of at most 0.08?
25
100
175
250
625
- 23. Multiple Choice
The process of producing pain-reliever tablets yields tablets with varying amounts of the active ingredient. It is claimed that the average amount of active ingredient per tablet is at least 200 milligrams. The Consumer Watchdog Bureau tests a random sample of 70 tablets. The mean content of the active ingredient for this sample is 194.3 milligrams, while the standard deviation is 21 milligrams. What is the approximate p-value for the appropriate test?
0.012
0.024
0.050
0.100
0.488
- 24. Multiple Choice
A survey was conducted to determine what percentage of college seniors would have chosen to attend a different college if they had known then what they know now. In a random sample of 100 seniors, 34 percent indicated that they would have attended a different college. A 90 percent confidence interval for the percentage of all seniors who would have attended a different college is
24.7% to 43.3%
25.8% to 42.2%
26.2% to 41.8%
30.6% to 37.4%
31.2% to 36.8%
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