Statistics Quiz Questions

test whether two groups differ significantly

The t test is used to

Standard deviation

Which of the following terms least belongs with the others?

49%

A researcher finds a correlation of .70 between popularity ratings and self-concept scores. What percentage of common association can be inferred between the two variables?

statement of the problem (purpose of study)

At the end of a well-written introduction, the reader should be able to predict the

nominal

Categories such as sex, city of residence, or political party affiliation are what kind of measure?

correlation

Determining the relationship between students' attitudes toward drugs and the frequency of drug usage is an example of a(n) ________ study.

generalizability of a study

External validity is the

skew

If a distribution is "significantly distorted" what is this called?

positively skewed

If the mean of a set of scores is greater than the median, what can be said about the distribution?

negatively skewed

If the median of a set of scores is greater than the mean, what can be said about the distribution?

reject the null hypothesis

If the obtained value is greater than the critical value, what should you do?

more precise and detailed

Moving from the nominal to the ratio levels of measurement, your data become...

ratio

Only this level of measurement has a true zero.

regression

Prediction studies use which of the following as the basic analysis technique?

spread of scores about the mean

The standard deviation represents the

Tools and techniques

Statistics describes a set of __________ that is used for describing, organizing, and interpreting information.

the critical value

The statistical value that is compared with the calculated value is called:

statistical power

The ability of a study to detect a real effect or relationship, if it actually exists is the definition of:

be a concise summary of the study

The abstract of a study should

consistency

The concept of reliability would be most closely associated with:

skewness

The term that describes the position of the hump in the curve of a distribution is

obtained value

The test statistic value calculated by the statistical procedure selected is known as the ___________.

the null hypothesis is true

Unless you have sufficient evidence otherwise, you must assume that...

descriptive statistics

Which of the following would be used to describe the type of statistical methods used to organize and describe the characteristics of a collection of data?

it assesses the relationship between two variables

Which statement is true regarding Pearson correlation coefficient?

all of the above statements are true

Which statement regarding a post hoc test is true?

coefficient of determination, r^2

Which statistic determines the variance common to or shared by two variables?

20

p < .05 means that there is less than 1 chance in ____ that any differences found were not due to the hypothesized reason.

positive

z scores which fall above the mean will be ___________________.

Random sample

"Every element in a population has an equal probability of being selected" is a definition of:

John Henry Effect

A researcher finds that the control group performs above its usual performance when compared with the experimental group. This effect is named the

research hypothesis

A researcher predicts that there will be a positive relationship between attitude scores and grade point average. This is an example of a

an independent t test

A researcher sought to find out which of two exercises was more effective in building endurance. One group used exercise A, and another group used exercise B. At the end of study, the researcher should compare the two groups' scores by

dependent t test

A researcher wishes to determine whether a treatment group made a significant improvement from the pretest (M = 25) to the posttest (M = 30). The correct statistical test to use to compare the two means is th

true

A standard deviation equal to 0 indicates no variance in your data.

research hypothesis

A statement that postulates a relationship between variables is referred to as a ___________.

t test

A study is designed to determine whether the addition of programmed instruction will produce greater achievement scores than the traditional lecture-discussion method. Participants are randomly assigned to two instructional groups. Both groups are tested at the end of the experimental period. What statistical test is indicated?

independent t test

A teacher wishes to compare the accuracy of throwing in 50 right- vs. 50 left- handed children. The appropriate statistical test is:

halo effect

A threat to the validity of rating scales is that the rater may tend to let his or her previous knowledge of the student in another capacity (e.g., another course) influence the rating. This threat is called the

significant

A(n) ____________ difference is due to some systematic influence and not due to chance.

all subject were tested on multiple occasions to compare performance with different levels of the independent variables

ANOVA with repeated measures means that:

true

All members of a sample are members of the population. true or false?

a journal article

An example of a primary reference is:

the effect size

Cohen's d is used to express:

usually offers more control, such as in a laboratory

Compared to applied research, basic research

the extent to which study results may be generalized

External validity may be defined as:

24 and 36

For a group of normally distributed scores with a mean of 30 and a standard deviation of 6, the middle 68% of the scores will be between

Test B

Four skills tests are tried as predictors of success in a tennis class. Each test correlates with later success as follows: test A, r = .27; test B, r = .90; test C, r = -.40; test D, r = -.65. The test that will most accurately predict success is

nominal, ordinal, interval, ratio

From least precise to most precise, list the four levels of measurement.

to make inferences from the sample to the population

How are inferential statistics most often used?

Which of the groups differ significantly from the others

If ANOVA has found a significant difference among four treatment groups, a follow-up test such as the Tukey is needed to determine

A cause-effect relationship exists between the two variables

If a Pearson r is statistically significant (p< 0.05), which statement is not true:

the null hypothesis is accepted

If a researcher sets the alpha level at 0.05 and the subsequent statistical analysis yields a p-value of 0.07, which of the following is true?

valid

If a test is measuring what it is designed to measure, it is said that the test is:

accept the null hypothesis

If the obtained value is less than the critical value, what should you do?

type 2 error

If the researcher fails to reject the null hypothesis when there really is a difference, this is an example of a

interval

If the underlying continuum we are measuring assumed equal intervals, at what level of measurement is the associated variable being measured?

no causation can be inferred

If there is a correlation of .80 between a test of scholastic aptitude and performance on an achievement test, one can infer that

stratified sample

If we wanted to construct a sample of exercisers based on age, sex, and aerobic fitness level we would probably construct a ______________.

ordinal

If you are interested in describing the order of variables along a continuum, what level of measurement would you use?

nondirectional research hypothesis

If you hypothesize that there will be a difference between test scores from classroom A and classroom B, but you do not hypothesize the direction, you would have a:

directional research hypothesis

If you were to hypothesize that test scores from classroom A will be higher than test scores from classroom B, you have a

15.87%

In a distribution with a mean of 100 and a standard deviation of 15, what is the probability that a score will be 115 or higher?

ordinal

In a local road race, Moe finishes in third place. This number is an example from a (an) _____________ scale.

experimental mortality

In a research study in which the treatment involved quite intense physical training, 40% of the participants in the treatment group dropped out as compared with 5% of the control group. This threat to internal validity is called

sample/larger population

In a study, a __________ is drawn from a ___________.

Did the author provide enough information that the study could be repeated?

In evaluating the method section of a research report, which is a very important question to keep in mind?

statistical regression

In experimental design, when comparisons are made of groups that have been selected on the basis of their extreme scores, the posttest means of the groups tend to move toward the mean of the entire population from which the extreme groups were selected. This threat to internal validity is called

one criterion from two or more predictors

In multiple regression, one is able to predict

critical value

In order to determine whether or not you will reject the null hypothesis, the test statistic value must be compared against the ___________.

left tail must be longer than the right

In order to say that a distribution is negatively skewed, which of the following must be true?

right tail must be longer than left

In order to say that a distribution is positively skewed, which of the following must be true?

tables and graphs displaying statistics

In the results section of a research report, the author should include

Hawthorne effect

Individuals performing well merely because they are being observed (and not necessarily because of any effect of treatment) are considered to be under the influence of the

interpreting

Inferential statistics involve _________ the data.

interpreting data

Inferential statistics is most often used for which of the following?

inability to experimentally establish cause and effect

The major weakness of epidemiologic studies is

Half the scores are above and below

The median is defined as a point in the distribution where:

0.05

The most commonly used significance level people are willing to take in testing the null hypothesis is:

ratio

The only measurement scale that has a meaningful absolute zero is the ______________ scale.

experimental research

The only type of research that can manipulate treatments and establish a cause and effect is

reduce large amount of data to a single meaningful value

The primary objective of statistical analysis is to:

Whatever level the researcher chooses

The probability level we would use to say the difference between two groups is not due to sampling error but is due to something real is

is based only on two scores

The range is not one of the better measures of variability since it:

30% of the total variance is accounted for by the treatments

The researcher obtained a significant F from the ANOVA. Omega squared was found to be .30. This is interpreted to mean that

central tendency

The single score which best represents all the scores in a distribution is the definition of

true

The standard deviation is sensitive to extreme scores. true or false?

average

The term "central tendency" is most closely related to which of the below?

population

There is always the possibility of error in statistics because the __________ is not directly tested.

inferential

There is always the possibility of error in the ___________ process.

median

This consists of the middle point of a set of values:

a directional research hypothesis

This is a hypothesis that reflects the difference between groups and also specifies the direction of the difference.

a nondirectional research hypothesis

This is a hypothesis that reflects the difference between groups, but does not specify the direction of the difference.

a null hypothesis

This is a statement of equality between sets of variables

a data point

This is another word for a single observation:

nominal

This is the least precise level of measurement.

ratio

This is the level of measurement where outcomes are based on some underlying continuum that also contains a true or absolute zero.

interval

This is the level of measurement where outcomes are based on some underlying continuum where it is possible to speak about how much more a higher performance is than a lower one:

ordinal

This is the level of measurement where outcomes can be rank ordered

nominal

This is the level of measurement where outcomes can only be placed into unranked categories.

ratio

This is the most precise level of measurement.

average

This is the value that best represents an entire group of scores.

mode

This measure of central tendency can be considered the least precise:

mean

This measure of central tendency can be considered the most precise:

50%

This percentage of scores fall on either side of the distribution:

68%

This percentage of scores fall within ± one standard deviation of the mean:

99%

This percentage of scores fall within ± three standard deviations of the mean

95%

This percentage of scores fall within ± two standard deviations of the mean:

Multiple regression

Three independent variables are used in an equation to predict bone mineral density. The appropriate statistical procedure for doing this is:

multiple regression

Three independent variables are used in an equation to predict bone mineral density. The appropriate statistical procedure for doing this is:

subtract the mean from the raw score and divide this difference by the standard deviation

To calculate a z score, you:

an independent t test

To find out which of two methods for learning a motor skill is more effective (ie. blocked vs. random), the correct statistical analysis is

whether the difference is expected to be in one direction only

Use of a one-tailed versus a two-tailed test of significance of the difference between two sample means depends on

mean

Variability is a measure of how much individual scores differ from the ______________.

range, standard deviation, and variance

What are the three tools used to assess variability?

they are equal to zero

What are true of z scores which are equal to the mean?

population size

What does the large N represent?

sample size

What does the small n represent?

significantly distort

What does the term "skew" mean?

arithmetic average

What is another term for the mean?

spread or dispersion

What is another term for variability?

variance

What is obtained by squaring the standard deviation?

population

What is the larger group from which a sample is drawn?

standard deviation

What is the most common measure of variability?

43

What is the range for the following set of scores: 34, 14, 17, 57, 22?

All of the above are correct

What is the result of changing the level of significance from .05 to .001?

Sample

What is the small subset of the population from whom you collect data called?

-x

What is the symbol used to represent the mean?

kurtosis

What is the term associated with how flat or peaked a distribution appears?

skewness

What is the term associated with the lack of symmetry in a distribution?

2.0

What is the z score for a raw score of 85 where the group mean is 75 and the standard deviation is 5?

15.87%

What percent of all scores fall above a z score of +1?

84.13%

What percent of all scores fall below a z score of +1?

Standard deviation

What statistic is used to show on average, how far each score in a distribution is away from the mean?

one-tailed test

What test would you want to use to test a directional research hypothesis?

two-tailed test

What test would you want to use to test a nondirectional research hypothesis?

nondirectional hypothesis

What type of hypothesis posits a difference between groups where the difference is not specified?

directional hypothesis

What type of hypothesis posits a difference between groups where the difference is specified?

Null hypothesis

What type of hypothesis posits no relationship between the variables in your study?

cause and effect

What type of relationship does experimental research best allow for?

longitudinal

What type of research may be used to research the same subjects over a long development period?

inferential statistics

What type of statistics employs the use of sample data that is used to infer information about the population?

type 1 error

When a researcher claims that there is a difference between treatments (i.e., rejects the null hypothesis) when there really is no difference, what type of error is this?

the result is unlikely to be a chance occurrence

When a researcher states that a result is significant, this means that

type 1 error

When an experimenter states that the level of significance is the .05 level, he or she is setting the probability of committing which type of error?

To describe how often something occurs

When are descriptive measures most often used?

true

When making a judgment in statistics, there is always some possibility of error. true or false?

negative skew

When the left tail of a distribution's curve is longer the right, what is this called?

ANOVA

When the purpose of the research is to determine the effects of one independent variable (e.g., four groups) on one dependent variable (e.g., self-concept), the best choice of a statistical analysis is

positive skew

When the right tail of a distribution's curve is longer the left, what is this called?

type 2 error

When you accept a false null hypothesis, you are making a ___________________.

Type 1 error

When you reject the null hypothesis when there is actually no difference between groups or relationships between variables, you are making a:

there is no difference between the vocabulary score of average and high ability students

Which hypothesis is stated in the null form?

is the probability of Type II error occurring

Which is not true regarding the level of significance?

it is a critique of the literature that includes results and limitations of studies, and attempts to collate studies by their findings

Which is the best description about the review of literature chapter?

statements a, b, and c are correct

Which is true regarding plagiarism?

nominal

Which level of measurement is concerned only with the characteristics of an outcome that fits into a category?

median

Which measure of central tendency is also known as the midpoint for a set of scores?

mean

Which measure of central tendency is most influenced by outliers?

standard deviation

Which measure of variability is a measure of the average distance from the mean?

range

Which measure of variability is most general, and hence least useful?

range

Which measure of variability should never be used alone to reach conclusions regarding the variance of a distribution?

asymptotic

Which of the following characteristics is associated with the "tails" of the normal curve?

interpreting data

Which of the following is NOT a use of descriptive statistics?

all of the above

Which of the following is a characteristic of experimental research?

mean, median, and mode are the same

Which of the following is a characteristic of the normal curve?

a one-tailed test

Which of the following is a directional test?

a two-tailed test

Which of the following is a nondirectional test?

null hypothesis

Which of the following is a statement of equality?

there is a positive relationship between a high-fat diet and weight gain

Which of the following is an example of a directional hypothesis?

there is a relationship between a high-fat diet and weight gain

Which of the following is an example of a nondirectional hypothesis?

true experimental

Which of the following is considered the strongest type of experimental design?

pre-experimental

Which of the following is considered the weakest type of experimental design?

an independent variable is introduced

Which of the following is not a feature of nonexperimental designs?

standard deviation

Which of the following is not a measure of central tendency?

mean

Which of the following is not a measure of variability?

a test can be valid without test scores being reliable

Which of the following is not a true statement?

beth finished in 437th place out of 987 runners in a 5K road race

Which of the following is not an example of interval or ratio data?

They are positive

Which of the following is true of z scores that fall above the mean?

they are negative

Which of the following is true of z scores that fall below the mean?

ratio

Which of the following levels of measurement provides the most information about a variable?

variability

Which of the following measures how scores differ from each other?

Type 2 error

Which of the following occurs when you accept the null hypothesis when it is really false?

you have made the correct decision

Which of the following occurs when you accept the null hypothesis when it is really true?

23, 37, 42, 51, 147

Which of the following sets of data illustrates skew?

7, 10, 11, 15, 19

Which of the following sets of scores has the greatest variability?

5, 4, 5, 6, 5

Which of the following sets of scores has the least variability?

implications of the results

Which of the following should be included in the discussion section of a research report?

n

Which of the following symbols represents sample size?

r^2

Which statistic determines the variance common to or shared by two variables?

decreasing your mean

Your current exam mean is 93.2. If you receive a 87 on the next exam, this will have the effect of:

increasing your mean

Your current exam mean is 97.2. If you receive a 99 on the next exam, this will have the effect of:

inferential

_______ statistics are often (but not always) the next step after you have some basic understanding of data.

sample

________ is to smaller group of data as population is to larger group of data.

descriptive

___________ statistics involve collecting, organizing, and summarizing data.

negative

z scores which fall below the mean will be ________________.

null hypothesis

"There is no difference in the weight between rats fed low-fiber diets and rats fed high fiber diets," is an example of a(n) _______________.

external validity

"To what populations, settings, treatment variables, and measurement variables can this effect be generalized?" might most appropriately be asked in relation to

Rejects the null hypothesis when it is true

A Type I error is said to occur when the researcher:

Accepts the null hypothesis when it is false

A Type II error is said to occur when the researcher

does not manipulate variables and hence cannot establish cause and effect

A basic characteristic of correlational research is that it

independence (no association) between the variables

A correlation of .00 between two variables indicates

negatively skewed

A distribution of scores in which almost the entire class scored very high, but a few students scored fairly low, would be:

positively skewed

A distribution of scores in which almost the entire class scored very low, but a few students scored fairly high, would be:

neither the researcher nor the participants know which participants receive the experiments treatment

A double-blind experiment is one in which

an educated guess

A hypothesis is best defined as ______________

effect size

A measure of meaningfulness that expresses the difference between the experimental and control group in standard deviation units is the

a statistical hypothesis that assumes that there is no difference among the effects of treatments

A null hypothesis is

if the null hypothesis is true, there is a 4% chance of getting a test statistic as extreme as, or more extreme than, the observe one

A p-value of 0.04 means what?

true

A population can be considered all of the occurrences with certain characteristics. true or false?

the extent to which the independent variable effects the dependent variable

Internal validity may be defined as:

observed and expected frequencies

The chi square analysis tells us the probability of obtaining a chance difference between:

100%

The entire normal curve contains this percentage of scores:

internal

The extent to which the results of a study can be attributed to the treatments used in the study is the definition of what kind of validity?

is the variable that is manipulated to see if it affects behavior or performance

The independent variable:

Did the independent variable really proud a change in the dependent variable?

The internal validity of an experimental design is concerned with what question?

move from a general description of the theoretical problem to the specific area to be studied

The introduction to a research report should

False

The less precise levels of measurement contain all the qualities of the scales above them. true or false?

a significance level

The level of chance or risk that you were willing to take is expressed as...