Psych Stats Chapter 9 and 10

A type II error is not possible....

When you have rejected the null hypothesis

Determining whether there is a logical reason to pair two scores in a two-sample experiment is necessary in deciding whether...

The design is a paired-samples or an independent-samples design

The statistical technique of null hypothesis statistical testing (NHST) is designed to test a hypothesis about...

a population parameter

Degrees of freedom are most closely related to...

a sample size

The actual amount of difference between the two populations the samples are from is most closely associated with...

effect size

The issue of the amount of difference between the mean of the population the sample is from and the mean of the null hypothesis population is the issue of...

effect size

A t test value that is larger than the tabled value of t

leads to rejection of the Ho and has a probability less than alpha, if the null hypothesis is true.

A t- test value that is larger than the tabled value of t...

leads to rejection of the null hypothesis and has a probability less than alpha, if the null hypothesis is true.

A "significant" event in statistics is one that is...

not attributed to chance

A correlation coefficient of .45 based on 18 pairs is, for a two tailed test,...

not significant

In the test of "propensity to fall in love" the mean of the 6 Montague was 54 and the mean of the 10 Capulets was 64. When a statistician compared the families with at t test, a value of 2.13 was obtained. If you adopt an alpha level of .05 (two-tailed test), you should conclude that the Capulets are...

not significantly different from the Montague's.

The p in p < .05 is the probability...

of the data obtained if the null hypothesis is true.

A student conducted a before and after study on college statistics students to see if the course improved ability to reason. In a later study, she used a mother-daughter sample to assess generational differences in attitudes toward abortion. Her two designs are...

paired; paired

The null hypothesis is a statement about..

populations

If the difference between a sample mean and the null hypothesis mean was in the rejection region of the sampling distribution.. it means that the difference is...

probably not due to chance.

If a 95 percent confidence interval about a difference between means i s 2.31 to 24.62, the null hypothesis may be...

rejected at the .05 level.

Which phrase goes with "not in the rejection region"?

retain the Ho

If the test value is less than the critical value on the table, ____ the null hypothesis even though yo could be making a ____ error.

retain; Type II

If a 95 percent confidence interval about a difference between means i s-2.31 to 24.62, the null hypothesis may be...

retained

What variable affects the size of the standard error of a difference?

sample size

A Pearson product- moment correlation coefficient of .34 obtained on 42 pairs of scores is, for a two-tailed test...

significant at the .05 level

the standard error of a difference, calculated from samples is a....

standard deviation

The p in p < .05 is the probability of...

the date obtained when H

"p < .05" means that...

the difference analyzed by a t test is statistically significant

The t distribution, as a smapling distribution, gives the probability of events when

the null hypothesis is true

The t- distribution, as a sampling distribution, gives the probability of events when...

the null hypothesis is true.

In an independent samples design, the null hypothesis is that...

the population means of one group is equal to that of a second group

The restriction that is built into the calculation of the standard error of the mean, the restriction that causes df to be N-1, is that...

the sum of the deviation scores must be zero.

The logic of null hypothesis statistical testing involves assuming that...

two populations have equal means and then using sample data to conclude that they are probably unequal.

A Type I error is possible...

when you have rejected the null hypothesis

A one-tailed test is proper when

you are only interested in finding out if the effect of a treatment is to increase the scores

A one-tailed test is proper when...

you are only interested in finding out if the effect of a treatment is to increase the scores.

which of the following is important in determining whether you will reject the null hypothesis?

- the size of the rejection region. - difference between the two population means. - the size of the sample size

For a two-sample t test, an effect size that qualifies as large is...

.80

When the t distribution is used to determine the significance of a correlation coefficient, the null hypothesis is that the population correlation coefficient is...

0.00

(T/F) Normally distributed populations with equal variances are most likely to give accurate p values for a t test.

True

(T/F) An effect size index of .05 or greater is considered large.

False

(T/F) As the value of p goes down, the value of d goes up.

False

(T/F) The alternative hypothesis is called the hypothesis of no difference.

False

(T/F) The denominator of a t test is difference between means.

False

(T/F) The formula for power is 1- mu.

False

(T/F) To be a small effect size, d must be .05 of less.

False

(T/F) Values of d larger than 1.00 are not possible.

False

(T/F) Power is the probability of a correct decisions when the null hypothesis is false.

True

(T/F) Power is the probability of not making a Type II error.

True

(T/F) The denominator of an independent-samples t test is a standard error of a difference.

True

(T/F) The probability figure that is the conventional cut-off for null hypothesis statistical testing is .05

True

Which of the following is a correct pairing?

Type I error, alpha

The best way to increase the power of statistical tests is...

Use large N's

Which of the following phrases uses "significant" in its statistical sense?

We measures how long it took groups to play "Clue " and how long to play "Monopoly". Clue happens significantly quicker.

(T/F) IF the null hypothesis is retained, the difference is not statistically significant.

True

(T/F) If a difference is statistically significant, the null hypothesis was rejected.

True

When an experimenter uses alpha = .05, the rejection region is

5 percent of the curve

Which alternative is most closely related to the concept of a two-tailed test of significance?

A divided rejection region

The reason for not reducing the alpha level to one in a million or even less is that...

Beta would be too large

"The difference between the two populations means was between .95 and .99" is a statement that is most closely related to...

Confidence intervals

An experimenter wanted to test the hypothesis that a particular sample came from a population with a mean of 10. The same had a mean of 8 and the standard error of the mean was .80. In order to test the experimenter's hypothesis with a t test, you would also need to know....

N

A hypothesis about a ____ is tested in statical hypothesis testing.

Population

Under which of the following conditions would you not use null hypothesis statical testing?

Population data are available

1- Beta is the ___ of a statistical test.

Power

A sampling distribution has one portion that represents differences that the investigator considers to be not due to chance. That part is called the...

Rejection Region

If the t test value is less than the critical value on the table, ____ the null hypothesis even though you could be making a ____ error.

Retain; Type II

The 95 percent confidence interval about a mean difference was -3.0 minutes to 6.5 minutes. The null hypothesis that the two population means are equal...

Should be retained

(T/F) A confidence interval about a mean difference gives a degree of confidence about the difference between two population means.

True

(T/F) A value of d such as 0.50 indicates a medium effect size.

True

(T/F) Both alpha and N help determine the amount of power at t test has.

True

Treat two groups exactly the same except for one things and then measure the individuals in both groups on some scale. Treating the two groups differently on the one thing constitutes...

The independent variable

"There is no difference in the two populations" is a statement of...

The null hypothesis

In an independent samples design, the null hypothesis is that....

The population mean of one group is equal to that of a second group.

If the t distribution is to produce an accurate probability figure for an independent- samples t test, which of the following must be true?

The populations the samples are from must have equal variances

The t distribution table in the appendix of your text is an example of a ____ distribution...

Theoretical

(T/F) A Type 1 error is possible when the null hypothesis is true.

True

Researchers control the probability of a Type I error in their experiment by setting the value of...

alpha

The choice of an alternative hypothesis has an effect on...

conclusions you may draw

Suppose you obtained a sample from a population for which the null hypothesis was true. On the basis of a t test, you failed to reject the null hypothesis. you have made a....

correct decision

A one-tailed test of significance produced a t equal to -2.30, significant at the .05 level. The design of this experiment...

could have been either a paired- or an independent- samples design.