Chapter 8 Quiz

A researcher administers a treatment to a sample of participants selected form a population with μ= 80. If a hypothesis test is used to evaluate the effect of the treatment, which combination of factors is most likely to result in rejecting the null hypothesis?

A sample mean much different than 80 for a large sample

Which of the following accurately describes a hypothesis test

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

What is measured by the numerator of the z-score test statistic?

The actual distance between M and μ

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

The average distance between M and μ that would be expected of H0 was true

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 (H1) say about the treatment?

The treatment causes a change in the scores

A researcher selects a sample and administers a treatment to the individual in the sample. If the sample is used for a hypothesis test, what does the null hypothesis (H0) say about the treatment?

The treatment has no effect on the scores

A researcher administers a treatment to a sample of participants selected from a population with μ= 80. If the researcher obtain a sample mean of M= 88, which combination of factors is most likely to result in rejecting the null hypothesis?

σ= 5 and a= .05

A researcher administers a treatment to a sample of participants selected form a population with μ= 80. If the researcher obtains a sample mean of M= 88, which combination of factors is most likely to result in rejecting the null hypothesis?

σ= 5 and n= 50

The critical boundaries for a hypothesis test are z= +/- 1.96. If the z-score for the sample data is z= -1.90, what is the correct statistical decision?

Fail to reject H0

A researcher is evaluating a treatment that is expected to increase scores. If a one-tailed test with a= .05 is used, then the critical region consists of z=scores less than -1.65

False

If a hypothesis test rejects the null hypothesis using an alpha level of a= .05, then the researcher report would include the statement, "p>.05."

False

With a=.05, how are the boundaries for the critical region determined?

Boundaries are drawn so there is 2.5% in each tail o the distribution

A researcher evaluates a treatment effect using a tailed hypothesis test with a= .05, and the decision is to reject the null hypothesis. if the researcher switched to a one-tailed test using the same sample, what decision would be made?

Definitely reject the null hypothesis with a= .05

For a hypothesis test evaluating the effect of a treatment on a population mean, what basic assumption is made concerning the treatment effect?

If there is a treatment effect, it will add (or subtract) a constant to each score

A researcher evaluates a treatment effect using a one-tailed hypothesis test with a= .05, and the decision is to reject the null hypothesis. if the researcher switched to a two-tailed test using the same sample, what decision would be made?

Might reject the null hypothesis with a= .05 but might not

Which of the following accurately describes the critical region?

Outcomes with a very low probability if the null hypothesis is true

A two-tailed hypothesis test is being used to evaluate a treatment effect with a=.05. If the sample data produces a z-score of z= -2.24, what is the correct decision?

Reject the null hypothesis

If a hypothesis test produces a z-score in the critical region, what decision should be made?

Reject the null hypothesis

A researcher conducts a hypothesis test to evaluate the effects of a treatment that is expected to increases scores. The hypothesis test produces a z-sore of z= 2.27. If the researcher is using a one-tailed test, what is the correct statistical decision?

Reject the null hypothesis with a= .05 but not with a= .01

Which of the following is directly addressed by the null hypothesis?

The population after treatment

A researcher conducts a hypothesis test to evaluate the effect of a treatment. the hypothesis test produces a z-score of z= 2.37. Assuming that the researcher is using a two-tailed test, what decision should be made?

The researcher should reject the null hypothesis with a= .05 but not with a= .01

A researcher expects a treatment to increase the scores for individuals in a population. The treatment is evaluated using a one-tailed hypothesis test, and the test produces z= +/-2.40. Based on this result, what is the correct statistical decision?

The researcher should reject the null hypothesis with either a= .05 or a= .01

If the research predict is that the treatment will decrease score, then the critical region for a directional test will be in the left-hand tail

True

In a research report, the term significant result means that the null hypothesis was rejected

True

The critical region for a hypothesis test consists of sample outcomes that are very unlikely to occur if the null hypothesis is true

True

The null hypothesis predicts a specific value for the population mean

True

A researcher expects a treatment to increase the score for individuals in a population. The researcher uses a one-tailed test with a= .01, then which o the following correctly identifies the critical region?

z> 2.33

A researcher is conducting an experiment to evaluate a treatment that is expected to increase the scores for individuals in a population that is known to have a mean of μ= 80. The results will be examined using a one-tailed hypothesis test. Which of the following is the correct statement of the null hypothesis?

μ≤ 80

If the sample data are in the critical region with a= .05, then the same sample data would still be in the critical region if a were changed to .01

False

The null hypothesis states that the sample mean ( after treatment) is equal to the original population mean ( before treatment)

False