Chapter 9: Hypothesis Testing

Which of the following could be a null hypothesis?
1. μ ≤ 5
2. μ > 5
3. μ < 5
4. μ ≠ 5
5. Any of the above could be a null hypothesis
The Type I error is the error of accepting Ho when it is false.
1. True
2. False
If a hypothesis test leads to the rejection of the null hypothesis
1. a Type I is always committed
2. a Type II error is always committed
3. a Type I error may have been committed
4. a type II error may have been committed
When hypothesis testing, if the level of significance is made smaller, the probability of rejecting Ho becomes larger.
1. True
2. False
The ABC Electronics Company claims that the batteries it produces have an average useful life of at least 100 hours. It is known that the population standard deviation is 20 hours. A test is undertaken to check the validity of this claim. With the level of significance set at .05, the critical value or values for the test based on a sample of 49 batteries is
1. z = -1.96 and +1.96
2. z = -1.435
3. z = -1.645
4. z = +1.645
The ABC Electronics Company claims that the batteries it produces have an average useful life of at least 100 hours. It is known that the population standard deviation is 20 hours. A test is undertaken to check the validity of this claim. If the random sample of 49 batteries resulted in an average life of 96 hours, can the manufacturer's claim be rejected at the .05 level of significance?
1. Yes the null hypothesis can be rejected.
2. No, do not reject the null hypothesis.
3. Not enough information is given to answer this question.
The ABC Electronics Company claims that the batteries it produces have an average useful life of at least 100 hours. It is known that the population standard deviation is 20 hours. A test is undertaken to check the validity of this claim. What is the p-value associated with the sample mean of 96 hours?
1. 0.0420
2. 0.0808
3. 0.4192
4. 0.96
New tires manufactured by a company in Findlay, Ohio, are designed to provide a mean life of at least 28,000 miles. Tests with 30 tires show a sample mean of 27,500 miles and a sample standard deviation of 1000 miles. Using a .05 level of significance, test whether there is sufficient evidence to reject the claim of a mean of at least 28,000 miles. What is the critical value?
1. -2.045 and 2.045
2. -1.699
3. -1.697
4. -1.645
5. 1.697
New tires manufactured by a company in Findlay, Ohio, are designed to provide a mean life of at least 28,000 miles. Tests with 30 tires show a sample mean of 27,500 miles and a sample standard deviation of 1000 miles. Using a .05 level of significance, test whether there is sufficient evidence to reject the claim of a mean of at least 28,000 miles. What is the test statistic value?
1. -2.74
2. -1.699
3. 1.699
4. 2.74
New tires manufactured by a company in Findlay, Ohio, are designed to provide a mean of at least 28,000 miles. Tests with 30 tires show a sample mean of 27,500 miles and a sample standard deviation of 1000 miles. Using a .05 level of significance, test whether there is sufficient evidence to reject the claim of a mean of at least 28,000 miles. What is the decision?
1. Reject the null hypothesis
2. Do not reject the null hypothesis
New tires manufactured by a company in Findlay, Ohio, are designed to provide a mean of at least 28,000 miles. Tests with 30 tires show a sample mean of 27,500 miles and a sample standard deviation of 1000 miles. Using a .05 level of significance, test whether there is sufficient evidence to reject the claim of a mean of at least 28,000 miles. What statement can be made about the p-value?
1. 0.025 < p < 0.05
2. 0.01 < p < 0.025
3. 0.005 < p < 0.01
4. p < 0.005
A magazine claims that 25% of its readers are college students. Of a random sample of 200 readers, 42 are college students. Use a .10 level of significance to test

What is the critical value?
1. -1.96
2. -1.645 and 1.645
3. -1.684 and 1.684
4. 1.96
A magazine claims that 25% of its readers are college students. Of a random sample of 200 readers, 42 are college students. Use a .10 level of significance to test

What is the decision?
1. Reject the null hypothesis
2. Do not reject the null hypothesis
A magazine claims that 25% of its readers are college students. Of a random sample of 200 readers, 42 are college students. Use a .10 level of significance to test

What is the p-value for this test?
1. 0.951
2. 0.1902
3. 0.21
4. 0.4049
If the level of significance of a hypothesis test is increased from .01 to .05, the probability of a Type II error
1. will also be increased form .01 to .05
2. will not be changed
3. will be decreased
4. Not enough information is given to answer this question