Stats Comp

Front 1

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

Back 1

a large sample and a small standard deviation

Front 2

Ifα is held constant at .05, what is the relationship between sample size, thecritical region, and the risk of a Type I error?

Back 2

d. There is no relationship between sample size,the critical region, and the risk of a Type I error.

Front 3

Increasing the alpha level (for example fromα = .01 to α = .05) _____.

Back 3

a. increases the probability of a Type I error b. increases the size of the critical region

c. increases the probability that the samplewill fall into the critical region

d. All of the other options are results ofincreasing alpha.

Front 4

Whichof the following is an accurate definition of a Type II error?

Back 4

c. failing to reject a false null hypothesis

Front 5

Aresearcher conducts a hypothesis test to evaluate the effect of a treatmentthat is expected to increase scores. Thehypothesis test produces a z-score of z = 2.37. If the researcher is using a one-tailed test, what is the correctstatistical decision?

Back 5

b. Reject the null hypothesis with either α =.05 or α = .01.

Front 6

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

Back 6

d. The t statistic does not require any information about the population.

Front 7

Twosamples from the same population both have M = 84 and s2 = 20,however one sample has n = 10 and the other has n = 20 scores. Both samples are used to evaluate ahypothesis that μ = 80 and to computeCohen’s d. How will the outcomes for thetwo samples compare?

Back 7

. The larger sample is more likely to rejectthe hypothesis but the two samples will have the same value for Cohen’s d.

Front 8

The range and the standarddeviation are both measures of variability.

Back 8

true

Front 9

Adding a constant value toevery score in a sample will change the standard deviation of the sample.

Back 9

False

Front 10

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

Back 10

True

Front 11

According to the centrallimit theorem, the standard error for a sample mean becomes smaller as thesample size increases.

Back 11

True

Front 12

A significant hypothesistest does not necessarily indicate a large treatment effect, so APA recommendsreporting effect sizes in research reports.

Back 12

True

Front 13

Generally speaking, the larger the effect size, sample size, or α level, the greater the power of a hypothesis test.

Back 13

True

Front 14

For a hypothesis test using a t statistic, the boundaries for the critical region will change if the sample size is changed.

Back 14

True

Front 15

Which of the following is an example of a discrete variable?

Back 15

True

Front 16

The average verbal SATscore for the entire class of entering freshmen is 530. However, if you select a sample of 20freshmen and compute their average verbal SAT score you probably will not getexactly 530. What statistical concept isused to explain the natural difference that exists between a sample mean andthe corresponding population mean?

Back 16

Sampling error

Front 17

Determining the classstanding (1st, 2nd, and so on) for the graduating seniorsat a high school would involve measurement on a(n) _____ scale of measurement.

Back 17

Ordinal

Front 18

A distribution ispositively skewed. Which is the mostprobable order, from smallest to largest, for the three measures of centraltendency?

Back 18

b. mode, median, mean

Front 19

A population distributionhas σ = 6. What position in this distributionis identified by a z-score of z = +2.00?

Back 19

c. 12 points above themean

Front 20

A sample of n = 20 scores is transformed intoz-scores. What is the mean for the setof 20 z-scores?

Back 20

0

Front 21

What z-score valueseparates the top 10% of a normal distribution from the bottom 90%?

Back 21

a. z = 1.28

Front 22

The distribution of samplemeans ____

Back 22

d. will be normal ifeither the population is normal or the sample size is n > 30.

Front 23

What happens to thestandard error of M as sample size increases?

Back 23

b. It decreases.

Front 24

Which of the followingaccurately describes a hypothesis test?

Back 24

c. an inferentialtechnique that uses the data from a sample to draw inferences about a population

Front 25

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

Back 25

a. increase thelikelihood of rejecting H0 and increase the risk of a Type I error

Front 26

What is a Type II error?

Back 26

c. concluding that atreatment has no effect when it really does

Front 27

The critical boundariesfor a hypothesis test are z = +1.96 and -1.96. If the z score for the sampledata is z = - 1.90, then what is the correct statistical decision?

Back 27

b. Fail to reject H0.

Front 28

If a hypothesis test isfound to have power = 0.70, then what is the probability that the test willresult in a Type II error?

Back 28

a. 0.30

Front 29

A sample of n = 25 scoresproduces a t statistic of t = -2.062. Ifthe researcher is using a two-tailed test, then which of the following is thecorrect statistical decision?

Back 29

c. The researcher would fail to reject the nullhypothesis with either α = .05 or α = .01.

Front 30

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

Back 30

The t statistic usesthe sample standard deviation in place of the population standard deviation.

Front 31

Which of the followingdescribes what a confidence interval does?

Back 31

It uses a sample meanto estimate the corresponding population mean.

Front 32

Which of the following isINCORRECT about effect size?

Back 32

a. Cohen’s d is onetype of effect size for a t test.

b. r2, ameasure of effect size, gives us the percentage of variance accounted for.

c. Effect sizeis only worth examining when a hypothesis test is significant.

d. Effect size is ameasure of treatment effect.

Front 33

Ina hypothesis test, a large value for the sample variance increases thelikelihood that you will find a significant treatment effect.

Back 33

False

Front 34

Thesample mean will always be exactly in the center of a confidence interval thatis estimating the value of the population mean.

Back 34

True

Front 35

For anindependent-measures research study, what is measured by Cohen’s d or r2?

Back 35

c. the size of the difference between the twotreatments

Front 36

Whichcombination of factors is most likely to produce a significant value for anindependent-measures t statistic?

Back 36

large samples and small variance

Front 37

What is stated by the null hypothesis (H0)for an ANOVA?

Back 37

a. There are nodifferences between any of the population means.

Front 38

Foran analysis of variance comparing three treatment means, H0 statesthat all three population means are the same and H1 states that allthree population means are different.

Back 38

False

Front 39

Posttests such as Scheffé are not necessary for an analysis of variance comparingonly two treatment conditions.

Back 39

True

Front 40

Ina two-factor ANOVA, what is the implication of a significant AxB interaction?

Back 40

The significance of the interaction has no implications forthe main effects.

Front 41

If the results of a two-factor experiment arepresented in a line graph, then what pattern appears in the graph if there isan interaction?

Back 41

d. the lines move toward each other or cross

Front 42

A researcher predicts that a special trainingcourse will be highly effective for females but will have little or no effectfor males. This researcher is predicting an interaction between training andgender.

Back 42

True

Front 43

What would the scatterplot show for data thatproduce a Pearson correlation of r = +.88?

Back 43

a. points clusteredclose to a line that slopes up to the right

Front 44

Whatcorrelation is obtained when the Pearson correlation is computed for data thathave been converted to ranks?

Back 44

a. the Spearmancorrelation.

Front 45

4. For an independent-measures research study, what is measured by Cohen’s d or r2?

Back 45

c. the size of the difference between the two treatments

Front 46

In a study evaluating the effectiveness of a new medication designed to control high blood pressure, one sample of individuals is given the medicine and a second sample is given an inactive placebo. Blood pressure is measured for each individual. For this study, what is the dependent variable?

Back 46

C. Blood pressure

Front 47

Which of the following is nota continuous variable?

Back 47

D. Number of children in a family

Front 48

Frequency distribution bar graphs are intended for use with

Back 48

either nominal or ordinal scales

Front 49

A sample of n = 25 scores has a mean of M = 11. If each score in the sample is multiplied by 6, the new mean would be __________.

Back 49

66

Front 50

After 5 points are added to every score in a distribution, the mean is calculated and found to be = 30. What was the value of the mean for the original distribution?

Back 50

25

Front 51

Which of thefollowing is a property of the mean?

Back 51

a.changing the value of a score will change the value of the mean

b.adding a constant to each score will add the same constant to the mean

c.multiplying each score by a constant will multiply the mean by the same constant

d.All 3 of the other choices are correct

Front 52

For a perfectly symmetrical distribution with µ= 30, what is the most probably value for the mode?

Back 52

d. cannot be determined from the informationgiven