Chapter 8 Section 1

Give the null and alternative hypotheses for the following.

The mean score of adults for a particular IQ test is reported to be 100.  A researcher believes this value is too low.

• The null hypothesis is that the mean score of adults for the particular IQ test is 100. The alternative hypothesis is that the mean score of adults for the particular IQ test is equal to 100.
• The null hypothesis is that the mean score of adults for the particular IQ test is 100. The alternative hypothesis is that the mean score of adults for the particular IQ test is greater than 100.
• The null hypothesis is that the mean score of adults for the particular IQ test is 100. The alternative hypothesis is that the mean score of adults for the particular IQ test is less than or equal to 100.
• The null hypothesis is that the mean score of adults for the particular IQ test is 100. The alternative hypothesis is that the mean score of adults for the particular IQ test is less than 100.

Give the null and alternative hypotheses for the following.

In a study of male runners on a treadmill for 6 minutes, the mean heart rate was 104.  In a new study of men between the ages of 18 and 25, a researcher believes the heart rate will be lower.

• The null hypothesis is that the mean heart rate of men between the ages of 18 and 25 on a treadmill for 6 minutes is equal to 104. The alternative hypothesis is that the mean heart rate will be lower than 104.
• The null hypothesis is that the mean heart rate of men between the ages of 18 and 25 on a treadmill for 6 minutes is equal to 100. The alternative hypothesis is that the mean heart rate will be lower than 104.
• The null hypothesis is that the mean heart rate of men between the ages of 18 and 25 on a treadmill for 6 minutes is equal to 110. The alternative hypothesis is that the mean heart rate will be lower than 104.
• The null hypothesis is that the mean heart rate of men between the ages of 18 and 25 on a treadmill for 6 minutes is equal to 104. The alternative hypothesis is that the mean heart rate will be higher than 104.

An Unusual Event is an event that has a probability of ​ (a)   or less.

• 5%
• 0.05%
• 50%
• 0.0005

The dean of a business school wants to determine whether the mean starting salary of graduates of her school is greater than $50,000. She performs a hypothesis test with the following null and alternative hypotheses:

H₀: μ = $50,000                       H_a: μ > $50,000

Suppose that the true mean is μ = $50,000 (i.e. H₀: μ = $50,000 is true) and the dean rejects H₀.

• Is this a Type I error, a Type II error, or a correct decision?

• Type I error
• Type II error
• Correct decision

The dean of a business school wants to determine whether the mean starting salary of graduates of her school is greater than $50,000. She performs a hypothesis test with the following null and alternative hypotheses:

H₀: μ = $50,000                       H_a: μ > $50,000

Suppose that the true mean is μ = $55,000 (i.e. H₀: μ = $50,000 is not true), and the dean rejects H₀.

• Is this a Type I error, a Type II error, or a correct decision?

• Type I error
• Type II error
• Correct decision

The dean of a business school wants to determine whether the mean starting salary of graduates of her school is greater than $50,000. She performs a hypothesis test with the following null and alternative hypotheses:

H₀: μ = $50,000                       H_a: μ > $50,000

Suppose that the true mean is μ = $55,000 (i.e. H₀: μ = $50,000 is not true), and the dean does not reject H₀.

• Is this a Type I error, a Type II error, or a correct decision?

• Type I error
• Type II error
• Correct decision