Stats Exam 1

Question 0

Takes numerical values for which arithmetic operations such as adding and averaging make sense

Answer 0

Quantitative variable

Question 1

Places an individual into one of several groups or categories

Answer 1

Categorical variable

Question 2

The — of a variable tells us what values it takes and how often it takes these values

Answer 2

Distribution

Question 3

The —‘lists the categories and gives either the count or the percent of individuals that fall I’m each category

Answer 3

Distribution of a categorical variable

Question 4

The most common graph of the distribution of one quantitative variable

Answer 4

Histogram

Question 5

A distribution is — if the left and right sides of the histogram are approx mirror images of each other

Answer 5

Symmetric

Question 6

A distribution is — if the right side of the histogram (containing half of the observations with larger values) extends much farther out than the left side

Answer 6

Skewed to the right

Question 7

The distribution is — if the left side of the histogram extends much farther out than the right side

Answer 7

Skewed to the left

Question 8

If the distribution is exactly symmetric then the — and — are the same

Answer 8

Mean and median

Question 9

In a — distribution, the mean is usually farther out n the long tail than the median

Answer 9

Skewed

Question 10

The — mark out the middle half

Answer 10

Quartiles

Question 11

The — lies one-quarter of the way up the list (larger than 25%of the observations)

Answer 11

1st quartile

Question 12

Lies three-quarters of the way up the list (larger than 75% of the observations)

Answer 12

Third quartile

Question 13

The distance between the first and third Quartiles

Answer 13

Interquartile range IQR

Question 14

Outliers falls more than — above the third quartile or below the first quartile

Answer 14

1.5 x IQR

Question 15

Measures the outcome of a study

Answer 15

Response variable

Question 16

Explains or influences changes in a response variable

Answer 16

Explanatory variable

Question 17

Shows the relationship between two quantitative variables measured on the same individuals

Answer 17

Scatterplot

Question 18

Two variables are — when above-average values of one tend to accompany above-average values of the other, and below-average values also tend to occur together

Answer 18

Positively associated

Question 19

Two variables are —when above-average values of one tend to accompany below-average values of the other and vice versa

Answer 19

Negatively associated

Question 20

The — measures the direction and strength if the linear relationship between two quantitative variables. R

Answer 20

Correlation

Question 21

A straight line that describes how a response variable y changes as an explanatory variable x changes. We often use these to predict the value of y for a given value of x

Answer 21

Regression line

Question 22

The difference between an observed value of the response variable and the value predicted by the regression line. Observed- predicted

Answer 22

Residual

Question 23

An observation is — for a statistical calculation if removing it would markedly change the result if the calculation

Answer 23

Influential

Question 24

The use of a regression line for prediction far outside the range of values of the explanatory variable x that you used to obtain the line

Answer 24

Extrapolation

Question 25

A variable that is not among the explanatory or response variables in a study and yet may influence the interpretation of relationships among those variables

Answer 25

Lurking variable

Question 26

Describes the relationship between two categorical variables

Answer 26

Two-way table

Question 27

The — of one of the categorical variables in a two-way table of counts is the distribution of values of values of that variable among all individuals described by the table

Answer 27

Marginal distribution

Question 28

A — of a variable is the distribution of values of that variable among only individuals who have a given value of the other variable.

Answer 28

Conditional distribution

Question 29

An association or comparison that holds for all of several groups can reverse direction when the data are combined to form a single group. This reversal is called —

Answer 29

Simpson’s paradox