a variable measured on an interval scale

a variable measured on a ratio scale

any continuous variable

any test whose scores are normally distributed

Question 2 0.5 pts

Which of these is a discrete measure?

How many points you earn on a test

How many inches you grew in a year

How many term papers are due this semester

How many hours you study for an exam

Question 3 0.5 pts

It is not possible to report the average score for data measured on what type of scale?

nominal

ordinal

interval

ratio

Question 4 0.5 pts

Jane’s percentile rank on a science exam is 78. This means that:

Jane answered 78% of the questions correctly on the exam

Jane’s score was equal to or greater than 78% of the other students’ scores

Jane achieved a score of 78% on the exam

Jane scored the same as 78% of the other students

Question 5 0.5 pts

Rudy scores 83% on a test. From that, we know that:

Rudy’s percentile rank is 83%

83% of the people who took the test scored the same or lower than Rudy

Rudy scored above average

Out of 100 possible points, Rudy scored 83 pointsQuestion 6 0.5 pts

Here is a set of scores: 3,6,2,9,4,7,5,7,7,5. If the scores were entered into a frequency table, what would be the cumulative frequency?

7

9

10

55

Question 7 0.5 pts

Your data consist of the average family size for all families within each of six different income levels. What type of visual display would best convey the data?

histogram

line graph

bar chart

frequency table

Question 8 0.5 pts

You are constructing a histogram for scores that range from 70 to 100 in whole points. Frequencies range from 3 to 10; that is, every whole-point score between 60 and 100 occurs at least 3 times, and at least one score occurs 10 times. Which of these would probably be the best range and size for the score intervals along the X-axis?

1-point intervals from 70 and 100

1-point intervals from 0 and 100

5-point intervals from 70 and 100

10-point intervals from 70 and 100

Question 9 10 pts

You are looking at a frequency table for a large number of scores. Without doing any further calculating, which measure of central tendency can you immediately report?

mode

median

mean

none of these

Question 10 10 pts

In a set of raw scores for a teacher-constructed test, what will be the shape of the distribution around the mean?

normal

bimodal

skewed

it could be distributed in any of these ways

Question 11 0.5 pts

From the standard deviation, we know something about the:

general location of most scores within a scores distribution

spread of scores within the scores distribution

shape of the scores distribution

frequency at each score value

Question 12 0.5 pts

You select a sample of 50 scores from a population of 2,000 scores. You compute the range and standard deviation on the sample of 50 scores. You then select another sample of 50 scores from the same population. What measure of dispersion is likely to vary most between your first and second samples?

the range

the standard deviation

they will both vary by the same amount

there is no way to know which one will likely vary most

Question 13 0.5 pts

Here is a set of scores: 5, 5, 8, 14, 22, 22. If the set of scores is changed to 6, 6, 8, 14, 21, 21, how will these changes affect the standard deviation?

It will decrease the standard deviation

It will increase the standard deviation

It will have no effect on the standard deviation

There is not enough information to tell

Question 14 0.5 pts

The probability of rolling a 3 on a die is .17 over the long term (under an infinite number of rolls). What is the probability of rolling a 3 on a single roll?

.00

.17

.83

1.00

Question 15 0.5 pts

The probability of drawing a heart from a deck of cards is .25 over the long term (under an infinite number of draws). What is the probability of getting a heart on a single draw?

.00

.25

.75

1.00

Question 16 0.5 pts

A market researcher obtains a list of all streets in a town. She randomly samples 10 street names from the list, and then administers survey questions to every family living on those 10 streets. What type of sampling is this?

simple random

stratified random

cluster

convenience

Question 17 0.5 pts

In an experiment to determine the effect of exercise on weight-loss among postmenopausal women who are employed outside the home, what is the DEPENDENT variable?

exercise

menopausal status

employment status

weight loss

Question 18 0.5 pts

“Dogs that receive regular veterinary care live longer than those who do not receive such care.” What type of hypothesis is this?

null

directional

non-directional

double-barreled

Question 19 0.5 pts

“There will be no difference in the activity level of hyperactive children given medication and those not given medication.” What type of hypothesis is this?

null

directional

non-directional

double-barreled

Question 20 0.5 pts

A researcher plans to conduct a one-tailed test of her hypothesis at the .05 error level. Just before running the experiment, she decides that a two-tailed test is more appropriate. If she does not adjust the error level, how much error will her new study permit in a single tail?

.10

.05

.025

There is not enough information to tell

Question 21 0.5 pts

Professor Stringent conducts his study at a .01 error level. Professor Lax conducts his study at a .10 error level. Whose study is the better study?

Professor Stringent’s

Professor Lax’s

Both professors’ studies are equally worthy

There is not enough information to tell

Question 22 0.5 pts

The probability of a score falling at or below a particular z score is .8734. If you reject the null hypothesis, what is your Type 1 error level?

87.34%

12.66%

0.13%

There is not enough information to tell

Question 23 0.5 pts

What is the probability of a Type 1 error if you reject the null hypothesis based on a z score of .50?

0%

50%

100%

It depends on the individual values of the raw scores

Question 24 0.5 pts

Assume that a population of scores is normally distributed with a mean of 50 and a standard deviation of 10. For samples of size 25, we would expect 95% of the sample means (not of the raw scores) to fall between what two values?

30 and 70

40 and 55

46 and 54

51 and 59

Question 25 0.5 pts

A population has a mean of 300 and a standard deviation of 25. You draw a random sample from that population. What is the sample’s most likely mean?

0

25

300

There is not enough information to tell

Question 26 0.5 pts

If the population mean is 50 and the standard deviation is 5, what is the normal deviate Z for a sample of 20 people with a mean of 46?

-4.46

-3.57

1.12

-0.25

Question 27 0.5 pts

A two-tailed t test study for a single sample of 28 participants yields a t of -2.35. Look up this value in a t-table. Given the fixed number of participants, what is the lowest tabled alpha level at which this t is statistically significant?

1%

2%

5%

10%

Question 28 0.5 pts

In a one-sample t test, if the observed sample mean turns out to be one that would rarely occur when the null hypothesis is true, what should the researcher do?

reject the null hypothesis

retain the null hypothesis

repeat the test until we get a more probable sample mean

change the level of significance (Type I error)

Question 29 0.5 pts

A research report says that t (63) = 1.99; p = .03. From that information, can you reject the null hypothesis with 95% confidence?

yes

no

it depends on the sample size

it depends on the size of the Type 1 error

Question 30 0.5 pts

Which of these confidence intervals would include the widest range of scores?

68%

95%

99%

All confidence intervals are a standard range

Question 31 0.5 pts

What is the mean of any sampling distribution of the difference between the means?

0

The same as the difference between the two sample means in the study

The square root of the combined sample size of the two samples in the study

It depends on the value of the raw scores in the two sampling distributions

Question 32 0.5 pts

For a very small sample size, you should expect the size of the standard error of the difference between the means to be:

larger than usual

about the same size as usual

smaller than usual

almost zero

Question 33 0.5 pts

In a two-sample t test, if the observed difference between the sample means turns out to be one that could easily occur when the null hypothesis is true, what should we do?

Reject the null hypothesis

Retain the null hypothesis

Repeat the test until we get a less probable difference between the means

Change the level of significance (Type 1 error)

Question 34 0.5 pts

Which of these would be a related samples study?

1. Amount of sugar added to coffee by men versus women

2. Running speed for soccer players pre-season versus post-season

3. Number of hours the members of a class study for a weekly quiz versus a unit exam

1 and 2 only

1 and 3 only

2 and 3 only

1, 2 and 3

Question 35 0.5 pts

The hypothesis testing procedure for comparing means of RELATED samples would be appropriate for comparing:

differences in the religious beliefs of best friends

the distance that 12-year-olds versus 14-year-olds can kick a soccer ball

final grades in a course taught by Professor Jones compared with final grades in a course taught by Professor Smith

birth weights of babies born to drug-addicted mothers and birth weights of babies born to mothers who are not drug-addicted

Question 36 0.5 pts

The hypothesis testing procedures for comparing means of INDEPENDENT samples would be appropriate for comparing:

IQ scores of children attending a public elementary school as they progress from grade to grade

husbands’ and wives’ attitudes toward higher education

male and female problem-solving skills (number of moves toward the correct solution) on a spatial puzzle task

software “usefulness” ratings by users who try both Software A and Software B

Question 37 10 pts

“Children whose parents smoke in their presence are more likely to develop asthma than children whose parents do not smoke in their presence.” How many tails should be used when looking up the t test statistic for this study?

one tail

two tails

either one tail or two tails (it doesn’t matter)

there is not enough information to tell

Question 38 0.5 pts

When subjects who are treated in the SAME way differ in performance, what accounts for their measured difference?

between-groups variation

within-groups variation

total variation

treatment variation

Question 39 0.5 pts

When subjects who are treated in the SAME way differ in performance, what accounts for their measured difference?

random error

the treatment

the IV (independent variable)

this cannot happen

Question 40 0.5 pts

“One way” means that:

there is only one correct way to calculate the test statistic

the results can be in only one direction

there is only one sample (group) in the study

there is only one IV (independent variable) in the study

Question 41 0.5 pts

The appropriate statistic to use when testing the hypothesis for a study with three treatment groups is a:

one-sample t test

two-sample t test

ANOVA F test

Pearson’s correlation coefficient

Question 42 0.5 pts

You have conducted an analysis of variance and found no statistical significance in the F. Should you then calculate a post hoc test?

Yes, to see where the hidden significance might lie

Yes, to locate the confounding variables that might have masked the effect

Yes, to validate your non-significant F

No, because there is there is no statistical significance to be found

Question 43 0.5 pts

You conduct an ANOVA at the .05 error level and find a significant F. You conduct a Tukey HSD post hoc test on the same data at the same .05 error level and find no significant difference between the particular groups. From these results, you know that:

the sample size in each group was not sufficient to pick up the effect detected by the F test

the variation within each group masked the variation between the groups

you should have conducted your Tukey HSD at the .01 error level

you have made a calculation error in either the F test or the Tukey HSD

Question 44 0.5 pts

Your chi-square study has 4 categories or conditions of the first variable and 4 levels or conditions of the second variable. How many degrees of freedom are in this study?

7

8

9

16

Question 45 0.5 pts

You are testing the hypothesis that the average salary of college graduates 1 year out of college is related to the graduates’ genders and to the graduates’ fields of study. What is the appropriate analytic technique for this study?

two-sample t-test

analysis of variance

chi-square goodness of fit

chi-square test of independence

Question 46 0.5 pts

You are testing the hypothesis that the grade point averages differs between college athletes and non-athletes. What is the appropriate analytic technique for this study?

two-sample t-test

Pearson correlation coefficient

chi-square goodness of fit

chi-square test of independence

Question 47 0.5 pts

In a correlational study, we seek to determine:

if the independent variable causes an outcome in the dependent variable

which variable is the cause and which variable is the effect

the direction of causation

how well one variable predicts another variable

Question 48 0.5 pts

In a scatterplot, the data for a negative correlation will graph in what direction?

from the bottom left to the upper right

from the upper left to the bottom right

parallel to the horizontal X-axis

parallel to the vertical Y-axis

Question 49 0.5 pts

In a scatter diagram, if one of the points does not fall on the straight line of best fit to the data points, then r cannot be:

0

+1.00 or -1.00

positive

negative

Question 50 0.5 pts

Which one of the following would most likely show a negative correlation?

verbal aptitude and number of books read per year

body weight and age at which puberty was reached

amount of alcohol ingested and driving ability

educational level and income

Question 51 0.5 pts

The usefulness of a screening test for selecting college students for inclusion in an Honors program implies what type of relationship between the screening test and college grade point average (GPA)?

positive

negative

curvilinear

perfect

Question 52 0.5 pts

Which of these correlations is the strongest?

-0.75

0.00

+0.50

+0.67

Question 53 0.5 pts

Assume that, for variables X and Y, the statistics are as follows:

Variable X Variable Y

Mean = 50 Mean = 100

Stand. Dev. = 10 Stand. Dev. = 20

rxy = +1.00

What would be the predicted score on variable Y for a person who scores 40 on variable X? (Note: This can be answered without any formulas or calculations)

40

80

100

120

Question 54 0.5 pts

If r = −1.00, which one of the following will be true?

Scores on X will be of no use in predicting scores on Y.

Scores on X can be perfectly predicted from scores on Y.

The scores on X and Y are both negative.

The relationship becomes difficult to interpret.

Question 55 0.5 pts

For the regression equation Y’ = bX + a, what is the value of the criterion for someone who scores 60 on the predictor, where the correlation is .75, and where the prediction line’s Y-intercept is 5?

45

48.75

50

55

Question 56 0.5 pts

You conduct a study with four uncorrelated predictors. Then you remove one of the predictors. How should the removal of this predictor change the R2?

it will go up

it will go down

it will stay the same

there is not enough information to tell

Question 57 0.5 pts

The main difference between a simple and multiple regression is:

the number of dependent variables

the number of independent variables

the scales of measure of the independent variables

the size of the samples

Question 58 0.5 pts

In a curvilinear relationship:

the variables are unrelated

a scatterplot provides little information about the variables

the trend of the variables changes direction

an additional variable is necessary to explain the relationship

Question 59 0.5 pts

Another term for a regression intercept is:

unexplained variance

collinearity

heterogenity

constant

Question 60 0.5 pts

Nationwide, undergraduate college enrollment by gender is 55% female and 45% male. A professor wants to know the opinions of male versus female undergraduates nationwide. To ensure equal representation of the two genders, what sampling method should the professor use?

simple random

stratified random

cluster

convenience