stats vocab

Question 1

Explanatory Variable

Answer 1

Attempts to explain the observed outcomes (x-independent)

Question 2

Response Variable

Answer 2

measures the OUTCOME of a study (y-dependent)

Question 3

Scatterplot

Answer 3

graph of ordered pairs of numbers consisting of the independent variable, x, and the dependent variable y. A visual way of describing the nature of the relationship between the variables.

Question 4

Direction

Answer 4

positive or negative correlation

Question 5

Form

Answer 5

Is it linear? Quadratic? Exponential?

Question 6

Strength

Answer 6

How close do the points follow the form. (connects to form)

Question 7

Outliers

Answer 7

observation that lies outside the overall pattern of the other observations

Question 8

Correlation

Answer 8

a statistical method used to determine whether a relationship between 2 variables exist

Question 9

Correlation coefficient

Answer 9

a measure of
1. form
2. direction
3. strength of a relationship b/w 2 variables

Question 10

Least Squares Regression Line (LSRL)

Answer 10

Line of best fit that represents the points of a scatterplot

Question 11

Slope of LSRL

Answer 11

Shows the rate of change.
“for every 1 x, we more # of y”

Question 12

Intercept of LSRL

Answer 12

The value of ^y (y hat) when x=0 called “starting point” of the LSRL

Question 13

Coefficient of determination (r^2)

Answer 13

a measure of the proportion of variation in y that is explained to be the regression line using x as the predicting variable

Question 14

High association does not imply Causation

Answer 14

Just b/c 2 varaibles end to increase and decrease together DOES NOT mean a change in ONE is causing a CHANGE IN THE OTHER.

Question 15

Residual

Answer 15

“left over” variation in the response variable after fitting the regression line
“expectations vs. reality”

Question 16

Influential observations

Answer 16

Individual points that are EXTREME in the x- direction may have a strong influence on the regression line

can be close to the LSRL

Question 17

Extrapolation

Answer 17

Making predictions using the LSRL for values outside the observed range
MUST USE CAUTION

Question 18

Lurking variable

Answer 18

A variable that has an important effect on the response. But is not included among the variables studied.

Question 19

Experiment

Question 20

y hat

Answer 20

predicted y-value

Question 21

y-direction

Answer 21

individual points with large residuals are outliers

Question 22

Residual plot

Answer 22

scatterplot of the regression residuals against the explanatory variable (x)

NO SYSTEMATIC PATTERN!!

Question 23

Least squares criterion

Answer 23

The sum of the squares of the vertical distances, from the points to the line be made as small as possible

Question 24

Regression line

Answer 24

also called a “best fitting line” is the line for which the sum of the squares of the residual is a minimum

Question 25

equation of regression line

Answer 25

Y^= a + bx

Question 26

Coefficient of non-determination

Answer 26

The unexplained variation, found by subtracting the coefficiernt of determination from 1.

Question 27

r^2

Answer 27

coefficient of determination

Question 28

Residual equation

Answer 28

y-y^

Question 29

Simple relationships

Answer 29

has only 2 variables under study

Question 30

Multiple relationships

Answer 30

many variables are under study

Question 31

Subjective

Answer 31

it can be just your opinion or what you think, and not everyone may think alike

Question 32

r

Answer 32

the average of the products of the standardized values of x and y

Question 33

Range of correlation coefficient

Answer 33

-1< r < 1
Going away from r
stronger negative (left)
stronger positive (right)

towards center
weaker negative (left)
weaker positive (right)