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.
