Deck 15: Appendices a and B Descriptive and Inferential Statistics

Question 1

As the sample size increases:

A) the standard error of the mean increases
B) the power of a test decreases
C) the probability of a type II error decreases
D) the probability of a type I error increases

Answer 1

the probability of a type II error decreases

Question 2

Which of the following is the most useful descriptive measure of dispersion?

A) range
B) variance
C) mean deviation
D) standard deviation
E) absolute deviation

Answer 2

standard deviation

Question 3

The ____ divides a distribution in half.

A) range
B) mean
C) mode
D) median
E) dispersion

Answer 3

median

Question 4

Failing to reject the null hypothesis when it is actually false is a:

A) type I error
B) type II error
C) standard error
D) silly
E) correct decision

Question 5

Statistically significant effects can vary in their strength,which is measured by:

A) the alpha level
B) probability,such as p
C) the t-test
D) the magnitude of effect
E) the probability of a type-I error

Question 6

The F statistic is:

A) a nonparametric test
B) a ratio of population variances
C) [between-groups variance]/[within-groups variance]
D) [within-groups variance]/[between-groups variance]

Question 7

A conservative statistical test is one that:

A) minimizes both type I and type II errors
B) minimizes type I errors but increases type II errors
C) minimizes type II errors but increases type I errors
D) decreases the chance of type II errors
E) always results in both errors increasing

Question 8

If experimental treatments produce an effect:

A) between-groups variance will increase
B) between-groups variance will decrease
C) within-groups variance will increase
D) within-groups variance will stay the same

Question 9

The mode is:

A) the arithmetic average
B) the middle score
C) the most frequent score
D) the least frequent score
E) the standard score

Question 10

A sample is to a population as a ____ is to a(n)____.

A) description; inference
B) statistic; inference
C) fact; datum
D) mean; standard deviation
E) statistic; parameter

Question 11

In a normal distribution,a score that is one standard deviation above the mean:

A) has a different X value as the point of inflection
B) has a z-score of 0
C) occurs about as often as the score one standard deviation below the mean
D) is higher than about 98 percent of the scores in the distribution

Question 12

An advantage of the median over the mean is that the median is:

A) easier to calculate
B) more sensitive to each of the sample scores
C) a measure of dispersion
D) less influenced by extreme scores
E) often found between the limits of a score

Question 13

As the size of a sample increases,the ____ of the distribution of sample means becomes ____.

A) mean; larger
B) mean; smaller
C) standard deviation; larger
D) standard deviation; smaller

Question 14

The Mann-Whitney U test is:

A) an example of a parametric statistic
B) a test that assumes that the underlying distributions are normally distributed
C) designed for two groups of scores
D) intended for within-subjects designs

Question 15

If the mean IQ is 100 and the standard deviation of the IQ scores is 11,then an IQ of 122 will have a z-score of:

A) 1.0
B) 0.0
C) 2.0
D) 2.5
E) -2.0

Question 16

Rejecting the null hypothesis when it is actually false is:

A) a type I error
B) a type II error
C) more likely with two-tailed tests
D) an error of chance
E) a correct decision

Question 17

The median is:

A) the arithmetic average
B) the middle score
C) the range
D) the most common score

Question 18

The ____ is the sum of all scores divided by the number of scores.

A) median
B) mean
C) mode
D) deviation
E) average

Question 19

The variance of a group of scores is just like the absolute mean deviation except that for the variance:

A) the absolute value of the differences is used instead of the squared value
B) the squared value of the differences is used instead of the absolute value
C) differences are based on the median not on the mean
D) differences are based on the mean instead of on the median

Question 20

The standard deviation is:

A) the square of the variance
B) larger than the mean
C) the variance
D) a measure of dispersion

Question 21

A sample is a subset of the population.

Question 22

The median is preferred to the mean when there are a few extreme scores.

Question 23

A type 2 error occurs when we falsely reject the null hypothesis when it is actually false.

Question 24

If the mean score is 200 and the standard deviation is 50,then a score of 50 is one standard deviation below the mean.

Question 25

In a multifactor analysis of variance,how the variables affect one another is called:

A) main effects
B) interaction effects
C) experimental effects
D) variance effects
E) a type II error

Question 26

Statistical power increases with sample size.

Question 27

The power of a statistical test determines how likely it is that the null hypothesis will be rejected.

Question 28

A one-tailed p value is always bigger than a two-tailed p.

Question 29

In a histogram,frequency of scores is on the abscissa.

Question 30

If an obtained score has a z-value of two or greater,then this score is greater than about 95% of all scores.

Question 31

Statistical tests that increase type 1 errors tend to decrease type 2 errors.

Question 32

In a normal distribution,the mean,median,and mode have the same value.

Question 33

A type 1 error is rejection of the null hypothesis when it is actually false.

Question 34

About 68% of all scores lie between -2 and +2 standard deviations in a normal distribution.

Question 35

The Greek letter sigma ( $\sigma$ )stands for the sample standard deviation.

Question 36

The standard error of the mean decreases as sample size increases.

Question 37

The null hypothesis can be rejected if the alpha value is less than or equal to .05.

Question 38

Parametric statistical tests assume that the level of measurement is at least an interval scale.

Question 39

A z-score of +1 is one standard deviation above the mean.

Question 40

The standard deviation is the sum of the squared deviations from the mean,divided by the number of scores.

Question 41

The basic F-ratio formula is between-groups variance divided by within-groups variance.

Question 42

Determining p or significance is all that is necessary to decide whether the results of an experiment are meaningful.

Question 43

The magnitude of effect tells us how wrong the null hypothesis is when it has been rejected.

Question 44

The Mann-Whitney test is a parametric test used to compare two independent samples of scores.

Question 45

In a 2 $\times$ 2 factorial ANOVA,there are four F ratios that are of importance.

Question 46

If an experiment has two independent variables,each with three levels (so,it is a 3 $\times$ 3),there are two main effects and one interaction that can be assessed in an ANOVA.

Question 47

In a factorial ANOVA with repeated measures,error variance for the F ratios is estimated by the interaction of subjects within treatments.

Question 48

The within-subjects t-test is used for the same kind of experimental design that the Wilcoxon test is used.

Question 49

The Wilcoxon test is a non-parametric test for comparing to independent samples.

Question 50

One should calculate a measure of magnitude of effect even when the null hypothesis cannot be rejected.