1. Biomedical researchers are testing a cancer treatment to see if it is safe for human use. This can be thought of as a hypothesis test with the following hypotheses.

• H0: the medicine is safe
• Ha: the medicine is not safe

The following is an example of what type of error?

The sample suggests that the medicine is safe, but it actually is not safe.

type I

type II

not an error

2. Biomedical researchers are testing a cancer treatment to see if it is safe for human use. This can be thought of as a hypothesis test with the following hypotheses.

• H0: the medicine is safe
• Ha: the medicine is not safe

The following is an example of what type of error?

The sample suggests that the food is not safe, but it actually is safe.

type I

type II

not an error

3. A manufacturer of a hair dye markets its color as lasting, on average, 200 washes without fading. A consumer group decides to test this claim by assessing the number of times that 30 women can wash their hair without the color fading and finds the average is 203 washes, with a standard deviation of 5.2.

The resulting p-value is 0; thus, the null hypothesis is rejected. The consumer group concludes that the manufacturer's claim that its hair color lasts, on average, 200 washes is inaccurate.

What type of error is possible in this situation?

type I

type II

not an error

both

4. A manufacturer of a hair dye markets its color as lasting, on average, 200 washes without fading. A consumer group decides to re-test this claim by assessing the number of times that 30 women can wash their hair without the color fading and finds the average is 200.05 washes, with a standard deviation of 1.5.

The resulting p-value is .82588; thus, the null hypothesis is not rejected. The consumer group concludes that the manufacturer's claim that its hair color lasts, on average, 200 washes is accurate.

What type of error is possible in this situation?

type I

type II

not an error

both

5. Suppose the results indicate that the null hypothesis should be rejected; thus, it is possible that a type I error has been committed.

Given the type of error made in this situation, what could researchers do to reduce the risk of this error?

Change the significance level from .05 to .001

Change the significance level from 0.05 to 0.1

Increase the sample size

6. Suppose the results indicate that the null hypothesis should not be rejected; thus, it is possible that a type II error has been committed.

Given the type of error made in this situation, what could researchers do to reduce the risk of this error?

Decrease the sample size

Use a z-test

Use a t-test

Only use the data given a normal distribution

None of the above