Stat practice1

Imagine that 86,999 penniless people live in the town of Centerville. Bill Gates, whose net worth is $87,000,000,000 moves into Centerville. Now the mean net worth is ______ and the median net worth is ______.

$1,000,000; 0

Seven students reported the following individual earnings from their sale of books: $7, $13, $3, $5, $2, $9, and $3. In this distribution of earnings, the mean is ______.

6

During the past year, Cindy and Bobby each read 2 books, but Greg read 25, Jan read 12, and Marcia read 9. The median number of books read by these individuals is ______.

9

______ are conditions that impact the obtained score rather than the qualities of the trait being measured.

Sources of error

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

There is a relationship between exercise and increased heart rate.

Correlation coefficients are used to describe what?

a group

A number that characterizes the "middleness" of an entire distribution is ______.

a measure of central tendency

In statistics, a sample is ______.

a subset of a group to which a law of nature applies

One- and two-tailed hypotheses are both types of ______ hypotheses.

alternative

Using a correlational design, a researcher found a relationship between the healthiness of one's heart and the amount of fish oil in one's diet. The researcher should conclude that ______.

although a relationship exists, one cannot infer that changes in one variable are causing changes in the other variable

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

average

What is another way of describing "measures of central tendency"?

averages

Which of the following refers to a correlation between two variables?

bivariate

If we calculate a correlation coefficient and we find that there is a relationship between the two variables, we ______.

cannot conclude that changes in one variable cause changes in the other variable

The two types of criterion validity are:

concurrent and predictive

Reliability means that the measure is ______ in measuring the construct, whereas validity means that the measure is ______ in measuring the construct.

consistent; accurate

The most difficult source of validity to establish is ______.

construct

If you want to know that a test is measuring a sociological construct, what type of validity would you use?

construct validity

The following are measures of validity:

content validity and criterion validity only

When looking at how one variable changes another variable, which of the following descriptive statistics would you want to use?

correlation

What is a collection of information also called?

data set

The variable that one uses to determine the outcome is known as ______.

dependent variable

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?

descriptive statistics

Seven students reported the following individual earnings from their sale of books: $7, $13, $3, $5, $2, $9, and $3. In this distribution of individual earnings, the mean is ______ the mode and ______ the median.

greater than; greater than

In general, a negative correlation means that as the values of one variable ______, there is a tendency for the values of the other variable to ______.

increase; decrease

In general, a positive correlation means that as the values of one variable ______, there is a tendency for the values of the other variable to ______.

increase; increase

Inferential statistics allow us to ______.

infer something about the population based on the sample

Inferential statistics involve ______ the data.

interpreting

Rater-to-rater consistency is a(n) ______ reliability.

interrater

The study of statistics will require you to ______.

learn how to compute and interpret statistical procedures correctly

The ______ is calculated by summing all of the numbers in a distribution and dividing by the total number of scores.

mean

A ______ variable comes between two variables of interest and explains the apparent relationship and a ______ variable affects both our variables of interest and explains the correlation between them.

mediating; confounding

The type of descriptive statistic that tells you the most frequently occurring value is the ______.

mode

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

mode

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

none of these

Concluding there is no effect of the independent variable is to the ______ hypothesis, as concluding there is an effect of the independent variable is to the ______ hypothesis.

null; alternative

H0 is to Ha as ______ hypothesis is to ______ hypothesis.

null; alternative

The score you actually get on a test is an example of the ______ score, and the TRUE, 100% accurate reflection of what you really know is an example of ______.

observed; true

When using a ______ hypothesis, the researcher predicts the direction of the expected difference between the groups.

one-tailed

In a study on the effects of the amount of sleep on driving performance, researchers predict that those in the group that is allowed more sleep will exhibit better driving performance. The researchers are using a ______ hypothesis.

one-tailed and directional

A directional hypothesis is also known as a ______ hypothesis and a nondirectional hypothesis is also known as a ______ hypothesis.

one-tailed; two-tailed

How often are the observed score and the TRUE scores the same?

rarely

The best-fitting line through a scatterplot is known as the ______.

regression line

Researchers want the sample they use for inferential statistics to be ______ of the population

representative

In an experimental design ______, whereas in a correlational design ______.

researchers assign each person an X score and then measure the score on the Y variable; researchers measure scores on variables that a participant has already experienced

When plotting correlational data, the appropriate graph to use is the ______.

scatterplot

We should do a scatterplot of the data when we compute a correlation because the scatterplot allows us to ______.

see the relationship between the two variables

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

skew

"A measure of how stable a test is over time" is an example of which of the following types of reliability?

test-retest

In statistics, a population is ______

the entire group

To know whether there is a relationship between two variables, you draw a line around the outer edges of a scatterplot. If there is a negative relationship, ______.

the scatterplot is elliptical and is slanted downward (left to right)

When are descriptive measures most often used?

to describe how often something occurs

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

tools and techniques

In a correlational analysis, N stands for the ______.

total number of pairs of scores

In a study of the effects of exercise on stress, researchers predict simply that there will be a difference in stress level between the exercise and no-exercise groups. The researchers are using a ______ hypothesis.

two-tailed

When using a ______ hypothesis, the researcher predicts that the groups being compared will differ, but does NOT predict how they will differ.

two-tailed

A test cannot be ______ if it is not ______.

valid; reliable

How does one know that the test, scale, and form of measurement actually measure what it is supposed to?

validity

This is calculated by multiplying values by the frequency of their occurrence, adding the total of all the products, and then dividing by the total number of occurrences:

weighted mean

Given that on one section of the SAT the mean is 500 and the standard deviation is 100, what is the approximate probability of a student scoring 700 or higher on the test?

0.02

Given that on one section of the SAT the mean is 500 and the standard deviation is 100, what is the approximate probability of a student scoring 300 or lower or 700 or higher on the test?

0.045

Given that on one section of the SAT the mean is 500 and the standard deviation is 100, what is the approximate probability of a student scoring 400 or lower or 700 or higher on the test?

0.18

Given that on one section of the SAT the mean is 500 and the standard deviation is 100, what is the approximate probability of a student scoring 300 or higher on the test?

0.98

The coefficient that shows perfect reliability is:

1.00

______ statistics involve collecting, organizing, and summarizing data.

Descriptive

______ statistics are used in the process of hypothesis testing.

Inferential

What does a correlation coefficient do?

It quantifies the pattern in a relationship.