Psych Stats exam 3

Which combination of factors will produce the largest value for the standard error?

A small sample and a large standard deviation

Which of the following accurately describes a hypothesis test?

An inferential technique that uses sample data to draw inferences about a population

alternative hypothesis

Any effect

What is the relationship between the alpha level, the size of the critical region, and the risk of a type 1 error?

As the alpha level increases, the size of the critical region increases, and the risk of a type 1 error increases

What is the consequence of a type 2 error?

Concluding that a treatment has no effect when it really does

If a hypothesis test produces a test statistic that is not in the critical region, what decision should be made?

Fail to reject the null hypothesis

Under what circumstances will the distribution of a sample means be normal?

If the population is normal OR if the sample size is greater than 30

Under what circumstances can a very small treatment effect still be significant?

If the sample size (n) is very large

What is the standard error of M, the sample mean?

It is the standard deviation of the distribution of population means

two-tailed test

Predict mean will change

Type 1 error

Telling man he is pregnant

type 2 error

Telling pregnant woman she is not pregnant

What is measured by the denominator of the Z-score test statistic?

The average distance between M an u that would be expected if H0 were true

Why are t statistics more variable than z-scores?

The extra variability is caused by variations in the sample variance

If a researcher is using a t-statistic to test a null hypothesis about a population, what information is needed from the population to calculate the t statistic?

The t-statistic does not require any information about the population

Which of the following is a fundamental difference between the t-statistic and a z-score?

The t-statistic uses the sample variance in place of population variance.

A researcher selects a sample and administers a treatment to the individuals in the sample. If the sample is used for a hypothesis test, what does the alternative hypothesis (HA) assume about the treatment?

The treatment causes a change in the scores

When is there a risk of a type 1 error?

Whenever the null hypothesis is rejected.

When n is small (less than 30), how does the shape of the t distribution compare to the normal distribution?

it is flatter and more spread out than normal distribution

Null Hypothesis (H0)

no difference