Statistics chapter 8

For any distribution, what is the z-score corresponding to the mean?

0

What is the consequence of Type 1 error?

Concluding that a treatment has an effect when it really has no effect

What is the consequence of a Type II error?

Concluding that a treatment has no effect when it really does

Which of the following correctly describes the effect of increasing the alpha level (for example, from .01 to .05)?

Increase the likelihood of rejecting H0 and increase the risk of a Type 1 error.

Is a standardized score necessarily a z-score?

No

Which of the following is an accurate definition of Type 1 error?

Rejecting a true null hypothesis

Any individual with a positive z-score has a score greater than the mean.

True

For a population with a mean of 80, any score greater than 80 will have a positive z-score.

True

In general, the null hypothesis states that the treatment has no effect on the population mean.

True

The mean for the distribution of sample means is always equal to the mean for the population from which the samples are obtained.

True

What position in the distribution corresponds to a z-score of z=+2.00?

above the mean by a distance equal to 2 standard deviations

Which of the following will increase the power of statistical test?

change the sample size from n=25 to n=100

The distribution of sample means

will be normal if either the population is normal or the sample size is n≥30

Which of the following z-score values represents the location closest to the mean?

z=+0.50