Question 1: The two properties about a set of measurements of a dependent variable that we are most interested in describing are:

frequency and average.

average and correlation.

central tendency and dispersion.

histograms and polygons.

Question 2: The ________________ is the sum of all the scores divided by the number of scores.

median

mean

mode

standard deviation

Question 3: The generally preferred measure of central tendency is usually the

range

mean

standard deviation

median

Question 4: Which of the following is the most useful descriptive statistic for measuring dispersion?

range

variance

mean deviation

standard deviation

Question 5: The standard deviation is

the square of the variance.

the square root of the variance.

smaller than the mean.

the difference between the highest and lowest scores.

Question 6: If the mean I.Q. is 100 and the standard deviation of I.Q. scores is 15, then an I.Q. of 130 will have a z score (or standard score) of

1.00

0.00

2.00

-2.00

Question 7: Inferential statistics allow you to decide whether a difference between the experimental and the control group is due to _______________ or ________________.

manipulation; chance

manipulation; experimental error

sampling error; independent variable

independent variable; experimental error

Question 8: The null hypothesis suggests that the two samples come from ___________ distribution(s), and the experimental hypothesis suggests that the two samples come from _____________ distribution(s).

different; different

different; the same

the same; different

the same; the same

Question 9: The power of a statistical test refers to its ability to

reject false null hypotheses.

reject false experimental hypotheses.

reject true null hypotheses.

reject true experimental hypotheses.

Question 10: Simple analysis of variance is used in designs having

one independent variable

more than one independent variable

more than one independent variable (IV) but less than four IVs

more than one dependent variable

Question 11: The number of participants in a study is denoted by

s.

n.

z.

r.

Question 12: A _____________ is a complete set of measurements.

sample

population

random sampling

parameter

Question 13: _____________ is one way of ensuring that a sample is representative of the population.

The two-tailed test

The between-subjects design

The sign test

Random sampling

Question 14: If we conduct an experiment on average young, white, college males, inferential statistics allow us to generalize to the population of

average young, white, college males.

college male students.

college students.

young adults.

Question 15: If we apply an alpha level of .05, and there really is no effect of the experimental manipulation, then one should make a Type I error

5% of the time.

10% of the time.

15% of the time.

95% of the time.

Question 16: Which of the following would be considered the most conservative alpha level?

.01

.05

.10

.15

Question 17: The prediction that alcohol slows reaction time is

nondirectional.

directional.

semidirectional.

partially directional.

Question 18: Two-tailed tests are _______________ conservative and ______________ powerful than one-tailed tests.

less; less

less; more

more; less

more; more

Question 19: The _____________ indicates the number of scores that are free to vary.

U

degrees of freedom

magnitude of effect

point biserial

Question 20: The ____________ is used to analyze the results when there are more than two groups.

t-test

z-test

analysis of variance

none of the above

Question 21: The __________ maintains that two conditions do not differ.

experimental hypothesis

level of confidence

law of effect

null hypothesis

Question 22: A conservative statistical test is one that

minimizes both Type I and Type II errors.

minimizes Type I errors, but increases the chance of Type II errors.

minimizes Type II errors, but increases the chance of Type I errors.

increases the chance of both Type I and II errors.

Question 23: What are inferential statistics used for?

summarize the mean and standard deviation of the data

estimate if differences between groups are by chance

describe the data from 2 unrelated groups

describe the relationship within a set of data

Question 24: Descriptive statistics are used to:

compare the signficance of the difference between 2 data sets

test the difference between the means

describe the observations

describe the type one error in an experiment

Question 25: Which of the following is not a characteristic of the normal curve:

bell-shaped

represents 100% of the scores under the curve

100 is at the center

allows us to determine rank