Name: ________________________________
Period: ____
CHAPTER 9 TEST REVIEW
Assume that you plan to use a significance level of α = 0.05 to test the claim that p1= p2, Use the given
sample sizes and numbers of successes to find the pooled estimate p (This is found in section 9-2,
NOT the pooled variance found in 9.3). Round your answer to the nearest thousandth.
1) n1= 100 n2= 100 ; Sample proportion 1=0.18 Sample proportion 2=0.12
A) 0.150 B) 0.387 C) 0.300 D) 0.188
Assume that you plan to use a significance level of α = 0.05 to test the claim that p1= p2. Use the given
sample sizes and numbers of successes to find the z test statistic for the hypothesis test.
2) A report on the nightly news broadcast stated that10 out of 108 households with pet dogs were
burglarized and 20 out of 208 without pet dogs were burglarized.
A) z=-0.102 B) z=0.000 C) z=-0.173 D) z=-0.041
3) The table shows the number satisfied in their work in a sample of working adults with a college
education
and in a sample of working adults without a college education.Assume that you plan to use a significance
level of α= 0.05 to test the claim that p1>p2. Find the critical value(s) forthis hypothesis test. Do the data
provide sufficient evidence that a greater proportion of those with a college education are satisfied in their
work?
College Education
No College Education
Number in sample
143
133
Number satisfied in their work 71
66
A) z= 1.645; no B) z=-1.645; yes C) z=± 1.96; no D) z=1.96; yes
Assume that you plan to use a significance level of α = 0.05 to test the claim that p1 = p2, Use the
given sample sizes and numbers of successes to find the P-value for the hypothesis test.
4) n1 = 50 n2 = 50
x1= 8
x2= 7
A) 0.7794 B) 0.6103 C) 0.3897 D) 0.2206
Use the traditional method to test the given hypothesis. Assume that the samples are independent and
that they have been randomly selected
5) In a random sample of 500 people aged 20-24, 22% were smokers.In a random sample of 450 people
aged25-29, 14% were smokers. Test the claim that the proportion of smokers in the two age groups is the
same. Use a significance level of 0.01.
Construct the indicated confidence interval for the difference between population proportions p1 p2. Assume that the samples are independent and that they have been randomly selected.
6) x1=36, n1=64 and x2=47, n2=71; Construct a 95% confidence interval for the difference between
population proportions p1- p2
A) -0.263 <p1-p2 <0.064 B) -0.294 <p1-p2 <0.757 C) 0.399 <p1-p2<0.726 D) 0.368 <p1-p2<0.757
Determine whether the sample is independent or dependent.
7) The effectiveness of a new headache medicine is tested by measuring the amount of time before the
headache is cured for patients who use the medicine and another group of patients who use a placebo drug.
A) Independent samples B) Dependent samples
Test the indicated claim about the means of two populations. Assume that the two samples are
independent simple random samples selected from normally distributed populations. Do not assume
that the population standard deviations are equal. The population standard deviation is unknown.
Use the traditional method or P-value method as indicated.
8) A researcher wishes to determine whether people with high blood pressure can reduce their blood
pressure,measured in mm Hg, by following a particular diet. Use asignificance level of 0.01 to test the
claim that the treatment group is from a population with a smaller mean than the control group. Use the
traditional method of hypothesis testing.
TREATMENT GROUP
CONTROL GROUP
n1 = 35
n2= 28
x1= 189.1
x2= 203 7
s1= 38.7
s2= 39.2
Assume that the two samples are independent simple random samples selected from normally
distributed populations. The population standard deviation is known.
9) A researcher was interested in comparing the amount of time spent watching television by women and
by men.Independent simple random samples of 14 women and 17 men were selected, and each person was
asked how many hours he or she had watched television during the previous week. The summary statistics
are as follows.
Women
Men
x1=12.5 hrs
x2=14.3 hrs
population standard deviation 1= 3.9 hrs
population standard deviation 2= 5.2 hrs
n1= 14
n2= 17
Construct a 99% confidence interval forµ1-µ2, the difference between the mean amount of time spent
watching television for women and the mean amount of time spent watching television for men.
Perform the indicated hypothesis test. Assume that the two samples are independent simple random
samples selected from normally distributed populations. Also assume that the population standard
deviations are equal (σ1 = σ2) but unknown.
10) A researcher wishes to determine whether the blood pressure of vegetarians is, on average, lowerthan
the blood pressure of nonvegetarians.Independent simple random samples of 85 vegetarians and 75
nonvegetarians yielded the following sample statistics for systolic blood pressure:
Vegetarians
Nonvegetarians
n1 = 85
n2 = 75
x1= 124.1 mmHg
x2= 138.7 mmHg
s1= 38.7 mmHg
s2= 39.2 mmHg
Use a significance level of 0.01 to test the claim that the mean systolic blood pressure for vegetarians is
lower than the mean systolic blood pressure for nonvegetarians. Use the P-value method of hypothesis
testing.
Assume that you want to test the claim that the paired sample data come from a population for
which the mean difference is µd = 0. Compute the value of the t test statistic.
11) A farmer has decided to use a new additive to grow his crops. He divided his farm into 10 plots and
kept records of the corn yield (in bushels) before and after using the additive. The results are shown below.
Plot: 1 2 3 4 5 6 7
8 9 10
Before 9 9 8 7 6 8 5 9 10 11
After 10 9 9 8 7 10 6 10 10 12
You wish to test the following hypothesis at the 1 percent level of significance.
H0: µ1= µ2 against H1: µ1≠ µ2
What is the value of the appropriate test statistic?
A) 5.014 B) 2.536 C) 2.033 D) 1.584
Construct a confidence interval for µd, the mean of the differences d for the population of paired
data. Assume that the population of paired differences is normally distributed.
12) Using the sample paired data below, construct a 90% confidence interval forthe population mean of all
differences x - y.
x 3.3 5.6 3.5 5.2 6.2
y 3.0 4.4 3.1 5.9 3.9
A) -0.37 <(µ1- µ2)< 1.77
B) 0.22 <(µ1- µ2)< 7.48
C) -0.07 <(µ1- µ2)< 1.47
D) -0.31 <(µ1- µ2)< 1.71
Use the traditional method of hypothesis testing to test the given claim about the means of two
populations. Assume that two dependent samples have been randomly selected from normally
distributed populations.
13) The table below shows the weights of seven subjects before and afterfollowing a particular diet fortwo
months.
Subject A
B
C
D E
F
G
Before 190 153 183 161 154 153 167
After 183 144 181 166 140 155 155
Using a 0.01 level of significance, test the claim that the diet is effective in reducing weight.
Test the indicated claim about the variances or standard deviations of two populations. Assume that
both samples are independent simple random samples from populations having normal distributions.
14) A researcher obtained independentrandom samples of men from two different towns. She recorded the
weights of the men. The results are summarized below:
Town A
Town B
n1= 41
n2= 21
x1= 165.1 lb x2= 159.5 lb
s1=29.8 lb
s2=26.1 lb
Use a 0.05 significance level to test the claim that there is more variation in weights of men from town A
than in weights of men from town B.
ANSWER KEY
1) A
2) A
3) A
4) A
5)10) H0: p1= p2. H1: p1≠p2.
Test statistic: z = 3.19. Critical values: z = ±2.575.
Reject the null hypothesis. There is sufficient evidence to warrantrejection of the claim that the
proportion ofsmokers in the two age groups is the same.
6) A
7) A
8) H0: µ1=µ2.
H1: µ1<µ2.
Test statistic: t=-1.477.
Critical value: -2.473.
Do notreject the null hypothesis. There is not sufficient evidence to support the claimthat the
treatment group is from a population with a smaller mean than the control group.
9) Use Za/2 and find the margin of error to construct the confidence interval.
10) H0: µ1=µ2 H1: µ1<µ2
Test statistic: t=-2.367
0.005 < P-value< 0.01
RejectH0. At the 1% significance level, there is sufficient evidence to support the claim that the mean
systolic blood pressure for vegetarians is lowerthan the mean systolic blood pressure for
nonvegetarians.
11) A
12) A
13) H0: µd= 0. H1: µd> 0.
Test statistic t= 1.954. Critical value: t = 3.143.
Fail to reject H0. There is not sufficient evidence to support the claim that the diet is effective in
reducing weight.
14) H0: σ1=σ2 H1: σ1>σ2
Test statistic: F=1.3.
Upper critical F value: 1.9938.
Fail to reject the null hypothesis.There is not sufficient evidence to support the claim that there is
more variation in weights of men from town A than in weights of men from town B.