STAT412
Final Exam
Practice Questions
1. Researchers want to see if men have a higher blood pressure than women do. A study is planned in which the
blood pressures of 50 men and 50 women will be measured. What's the most appropriate research hypothesis about
the means of the men and women?
A) the sample means are the same
B) the sample mean will be higher for men
C) the population means are the same
D) the population mean is higher for men than for women
2. The time taken to deliver a pizza has a uniform probability distribution from 20 minutes to 60 minutes. What is
the probability that the time to deliver a pizza is at least 32 minutes?
A) .125
B) .300
C) .700
D) .875
3. A null hypothesis is that the mean cholesterol level is 200 in a certain age group. The alternative is that the mean
is not 200. Which of the following is the most significant evidence against the null and in favor of the alternative?
A) For a sample of n=25, the sample mean is 220
B) For a sample of n=10, the sample mean is 220
C) For a sample of n=50, the sample mean is 180
D) For a sample of n=20, the sample mean is 180
4. Which of the following correlation values indicates the strongest linear relationship between two quantitative
variables?
A) r = 0.30
B) r = 0.65
C) r = 0.00
D) r = 0.50
5. A student survey was done to study the relationship between class standing (freshman, sophomore, junior, or
senior) and favorite type of take-out food (pizza, Chinese food, burgers, sandwich, or other). The chi-square test
statistic was 25. Approximate the p-value.
A)
B)
C)
D)
.01 < p < 0.025
.025 < p < .05
.05 < p < .075
None of the above
6. Which of the following is a research question that could be addressed using a one-way analysis of variance?
A) Does mean blood pressure differ for three different age groups?
B) Does the variance of blood pressure differ for three different age groups?
C) Are the proportions of people who oppose capital punishment different for three different age groups?
D) Is there a relationship between political party preference and age?
7. The following is a scatterplot of the calories and sodium content of several brands of meat hot dogs. The leastsquares line has been drawn in on the plot.
Predicting value of sodium content for a brand of hot dogs having 300 calories is called
A) contingency.
B) extrapolation.
C) causation.
D) correlation.
8. In the General Social Survey, respondents were asked “If your party nominated a woman for President, would you
vote for her if she were qualified for the job?” A two-way table summarizing the results for 953 respondents, by
gender, is shown below:
Gender
Female
Male
Total
Yes
488
335
823
No
66
64
130
Total
554
399
953
If the null hypothesis were true, what is the expected number of women in the sample who would give a “No”
response to having a female president?
A)
B)
C)
D)
54.4
66.0
75.6
None of the above
9. Suppose that the least squares regression line for predicting y from x is ŷ = 100 + 1.3x. Which of the following is
a possible value for the correlation between y and x?
A) 1.3
B) –1.3
C) –0.5
D) 0.5
10. Using a sample of 300 children aged 10 to 12 years old, a child psychologist examines how scores on a “violent
behaviors” index relate to gender and amount of television watching per day (less than 2 hours, 2 to 4 hours, more
than 4 hours). In his report, the psychologist writes, “The effect of the amount of television watching on the violent
behaviors index was more pronounced for males than for females.” The sentence quoted in the previous sentence
indicates that
A) amount of television watching and gender are confounding variables
B) amount of television watching and gender are interacting variables
C) there is a main effect of gender
D) amount of television watching and the violent behaviors score are not related
11. An experiment is conducted to compare the starting salaries of male and female college graduates who find
jobs. Pairs are formed by choosing a male and a female with the same-major and similar grade point averages.
Suppose a random sample of ten pairs is formed in this manner and the starting salary of each person is conducted.
Pair
Male
Female
1
$34,300
$33,800
2
36,500
36,600
3
35,400
34,800
4
33,500
33,500
5
38,500
37,600
6
32,800
33,000
7
34,500
34,200
8
36,200
35,100
9
33,400
33,200
10
34,200
33,500
What statistical procedure should be used to see if there is any mean difference in the salaries for males and
females?
A) Chi-Square Goodness-of-Fit test
B) Pooled-t Test
C) Chi-Square Test of Independence
D) Paired-t Test
12. An experiment consists of flipping a fair coin once and rolling a fair die once. What is the probability of
observing a Head or a six
A) 1/12
B) 6/12
C) 7/12
D) 11/12
13. Suppose the present success rate in the treatment of a particular psychiatric disorder is 65%. A research group
hopes to demonstrate that the success rate of a new treatment will be better than this standard. Which of the
following describes a type 1 error for this problem?
A) Claiming that the success rate of the new treatment is greater than 65% when really it isn't.
B) Failing to decide that the success rate is greater than 65% when actually it is.
C) Using a one-sided alternative hypothesis when a two-sided alternative should have been used.
D) Using a two-sided alternative hypothesis when a one-sided alternative should have been used.
14. Use the given claim and the observed test statistic value to find the p-value.
Claim: The mean systolic blood pressure of women aged 40-50 in the U.S. is greater than 126 mmHg.
Test statistic value: z = 1.50
A)
B)
C)
D)
.1336
.0668
.9332
none of the above
15. The average time taken to complete an exam, X, follows a normal probability distribution with mean = 60
minutes and standard deviation 30 minutes. By what time should 67% of the students have finished the exam? (i.e.
What is the 67th percentile for X?)
A) 60.0 minutes
B) 73.2 minutes
C) 77.9 minutes
D) 82.5 minutes
16. A sample of size 36 is to selected from a normal population with =100 and =12. Find the probability that the
sample mean will differ from  by more than 2?
A)
B)
C)
D)
.3174
.1587
.8650
.4325
17. For a random sample of n=203 adults in a survey, here is a summary of responses to “How long did you sleep
last night?”
Variable
N Mean
sleep
203 6.42
StDev
1.56
SE Mean
0.11
What confidence level would be associated with the interval 6.42  0.255 as a confidence interval for the population
mean ?
A) 90%
B) 95%
C) 98%
D) 99%
18. The Los Angeles Times (Oct. 17, 1984) reported the color distribution for plain M&M’s was: 40% brown, 20%
yellow, 20% orange, 10% green, and 10% tan. Each piece of candy in a random sample of 100 plain M&M’s was
classified according to color, resulting in the given data.
Frequency
Brown
45
Yellow
13
Orange
17
Green
7
Tan
18
Determine the value of the test statistic for the above data.
A) 2.45
B) 6.78
C) 10.83
D) 13.98

19. A doctor gives a patient a test for a particular cancer. Before the results of the test, the only evidence the doctor
has to go on is that 1 woman in 1000 has this cancer. Experience has shown that, in 99 percent of the cases in which
cancer is present, the test is positive; and in 98 percent of the cases which it is not present, it is negative. If the test
turns out to be positive, what probability should the doctor assign to the event that cancer is present?
A) .253
B) .671
C) .019
D) .047
20. Consider a test of Ho:  = 65 versus Ha:  > 65. If the test uses  = 10, and a sample of size 50, what is
the probability of failing to reject Ho if the population mean is equal to 68? That is, what is the probability of making
a type-2 error if the population mean is equal to 68?
A) .5236
B) .4364
C) .3090
D) .2156