Hypothesis Testing Answers

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5

Zachary completes a hypothesis test and finds that he rejects the null hypothesis. Which statement gives a reason for rejecting the null hypothesis?

A
The z-statistic is less than 0.
B
The z-statistic lies in the critical region.
C
The z-statistic lies outside the critical region.
D
The z-statistic is greater than 0.
7

David wants to complete a hypothesis test with the least amount of probability for error. If he sets the significance level to 1%, assuming his sample is truly random, what else could he adjust in the test in order to reduce error?

A
He could change the population mean.
B
He could increase the sample size.
C
He could change the population standard deviation.
D
He could decrease the sample size.
9

Tyesha found that the z-statistic was 2.1 and that the critical z-values were -1.96 and 1.96. Which of the following is a valid conclusion based on these results?

A
One can reject the null hypothesis.
B
One can reject the alternate hypothesis.
C
One can accept the null hypothesis.
D
One cannot accept or reject the null hypothesis.
11

A recent survey of 8,000 high school students found that the mean price of a prom dress was $195.00 with a standard deviation of $12.00. Alyssa thinks that her school is more fashion conscious and that students spent more than $195.00. She collected data from 20 people in her high school and found that the average price spent on a prom dress was $208.00. Which of the following are the correct null hypothesis and alternate hypothesis?

A
H0: ; Ha:
Option A
B
H0: ; Ha:
Option B
C
H0: ; Ha:
Option C
D
H0: ; Ha:
Option D
12

A consumer protection group randomly checks the volume of different beverages to ensure that companies are packaging the stated amount. Each individual volume is not exact, but a volume of iced tea beverages is supposed to average to 300 mL with a standard deviation of 3 mL. The consumer protection group sampled 20 beverages and found the average to be 298.4 mL. Using the given table, which of the following is the most restrictive level of significance on a hypothesis test that would indicate the company is packaging less than the required average 300 mL?Upper-Tail Valuesa5%2.5%1%Critical z-values1.651.962.58

A
1%
B
2.5%
C
5%
D
10%
13

A researcher collated data on Americans’ leisure time activities. She found the mean number of hours spent watching television each weekday to be 2.7 hours with a standard deviation of 0.2 hours. Jonathan believes that his football team buddies watch less television than the average American. He gathered data from 40 football teammates and found the mean to be 2.3. Which of the following are the correct null and alternate hypotheses?

A
H0: ; Ha:
Option A
B
H0: ; Ha:
Option B
C
H0: ; Ha:
Option C
D
H0: ; Ha:
Option D
14

A recent survey of 8,000 high school students found that the mean price of a prom dress was $195.00 with a standard deviation of $12.00. Alyssa thinks that her school is more fashion conscious and spent more than $195.00. She collected data from 20 people in her high school and found that the average price spent on a prom dress was $208.00. Which of the following is the correct z-statistic for this situation?

A
0.24
B
4.84
C
7.51
D
96.90

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