Psychology 104

Even if the population distribution is unknown, we can assume that the shape of the distribution of sample means is approximately normal if sample size is greater than or equal to ______. A. 120 B. 30 C. 36 D. 5

30

If s = 12 and N = 36, then estimated standard error equals to ______. A. 2.0 B. 12/36 C. 0.5

2.0

What is the critical t score if you are testing a two-tailed hypothesis with df = 44? (α level of .05) A. 1.680 B. 2.414 C. 1.679 D. 2.015

2.015

Consider a study in which the sum of squares (SS) based on an experimental group of 10 participants is 70, and the SS based on a control group of 20 participants is 50. The pooled variance of this study is ______. A. 2.075 B. 4.285 C. 2.00 D. 4.00

4.285

A population has a mean of 75 and a standard deviation of 15. If you randomly sample nine people from the population, the standard error will be equal to ______. A. 2.0 B. 5.0 C. 0.2 D. 1.7

5.0

If s = 15 and the estimated standard error is 5, then the sample size must be equal to ______. A. 15.5 B. 3 C. 12 D. 9

9

You must always use estimated standard error for t score calculation. A. True B. False

True

When you have means from two different samples, it is best to conduct ______. A. one-sample t test B. dependent samples t test C. independent samples t test D. ANOVA

independent samples t test

If you are testing a(n) ______ hypothesis, then the critical region will be ______ when α = .05. A. one-tailed; 5% B. two-tailed; 5% C. one-tailed; 2.5% D. null; 2.5%

one-tailed; 5%

In independent-samples t test, you calculate the ______ first, then calculate the ______. A. sample means; difference of the means B. difference scores; mean of the difference scores C. difference scores; population means D. population means; difference of the means

sample means; difference of the means

The denominator of one-sample z test is also known as ______. A. standard error B. sample standard deviation C. variance of distribution of means D. population standard deviation

standard error

What is the main difference between z score and t score? A. t Scores are used when the population standard deviation is unknown. B. t Scores are used whenever the sample size is less than 30. C. t Scores are only used when inferences are made about other samples. D. t Scores are used when the study requires a one-tailed hypothesis.

t Scores are used when the population standard deviation is unknown.

The sample mean of depression scores of 16 fifth graders was 4.4 with standard deviation of 8. If the population mean of this depression score is 6, what is the calculated t score for this sample? A. -0.8 B. +3.2 C. -1.6 D. +0.8

-0.8

With an independent-samples t test, you will usually compare the difference of sample means to ______. A. 0 B. -1 C. +1 D. It varies from sample to sample.

0

Consider a study in which the sum of squares (SS) based on an experimental group of 15 participants is 100, and the SS based on a control group of 31 participants is 250. The estimated standard error of this study is ______. A. 2.82 B. 0.89 C. 0.79 D. 7.95

0.89

A researcher states an alternative hypothesis that the exercise improves physical health. Which is a possible null hypothesis corresponding to this alternative hypothesis? A. Physical health is not impacted by exercises. B. There is no effect of exercise on physical health. C. Exercise worsens physical health. D. Exercises worsens or has no impact on physical health.

Exercises worsens or has no impact on physical health.

Since we have two samples in a study with two different sample sizes, we will have two estimated standard errors to calculate. A. True B. False

False

When we calculate an inferential statistic looking at mean differences, the numerator is the __________________ and the denominator is the ______________________. A. actual mean difference, mean difference expected by chance due to sampling B. mean difference expected by chance due to sampling, actual mean difference C. population mean, sample mean D. sample mean, population mean

actual mean difference, mean difference expected by chance due to sampling

Central limit theorem indicates that as the sample increases, the distribution of sample means would ______. A. become asymmetrical B. become positively skewed C. approach a normal distribution D. become more uniform

approach a normal distribution

A research design where one group is tested in one condition and another group is tested in another condition is called ______. A. between-subjects design B. within-subjects design C. twin study D. matched-pair design

between-subjects design

A standard error of the mean is a standard deviation of a ______. A. population B. sample C. distribution of sample means D. individual scores

distribution of sample means

The denominator of the t score formula for the independent-samples t-test is ______. A. estimated standard error B. population standard error C. estimated pooled standard deviation D. estimated pooled variance

estimated standard error

You make a Type I error when you ______. A. fail to reject H1when it is false B. fail to reject H0 when it is false C. reject H1 when it is true D. reject H0 when it is true

reject H0 when it is true

A population has a mean of 75 and a standard deviation of 15. You randomly sample nine people from the population, and the mean of the nine people was 80. What is the z score of your sample mean? A. 1.3 B. 1.0 C. 0.7 D. 2.4

1.0

What is the critical t score if you are testing a one-tailed hypothesis, α level of .05 with df = 35? A. 2.021 B. 2.042 C. 1.333 D. 1.690

1.690

In SPSS, when you run a one sample t test (one tailed), the p value that is given in the output is the specific value you will use to compare to your alpha level so that you can either reject, or fail to reject, the null hypothesis. A. True B. False

False

If your p value is 0.15 and you have chosen α of .10, then a statistical decision is to ______. A. retain the null hypothesis B. reject the alternative hypothesis C. retain the alternative hypothesis D. reject the null hypothesis

retain the null hypothesis

Suppose 36 participants complete an experiment where ads are presented subliminally during a task)(e.g. Coke ads are flashed at very fast rates during movie ads). Participants are then given a recognition test of images of the ads, where two images are presented and participants must choose which of the two was presented earlier. Both men and women (18 of each gender) participate in the study and the researcher predicts that the recognition accuracy will differ across gender. The difference between the sample means in this study was 6%. The SS for the men was 250 and the SS for the women was 150. What is your t value? A. t=5.45 B. t=5.25 C. t=8.95 D. t=7.85

t=5.25

All of the following statements are true about independent-samples t tests EXCEPT ______. A. they can be used when the population variance is unknown B. they involve the same hypothesis-testing procedures as one-sample z test C. they can be used when the sample means are unknown D. they compare the calculated t scores from a sample to a t distribution

they can be used when the sample means are unknown

If the p value from the output of SPSS is .02, then ______. A. you fail to reject H0 if α = .05 B. you fail to reject H1 if α = .05 C. you can reject H0 if α = .05 D. you can reject H1 if α = .05

you can reject H0 if α = .05