Quantitative Stats Chapter 4

Front 1

correlation

Back 1

the extent to which to or more things are related to one another.

Front 2

direct relationship

Back 2

correlation coefficient with a positive sign. as one increases, so does the other. to the right and up.

Front 3

a correlation coefficient of zero can be achieved if (2 ways)

Back 3

1. one of the variables actually is a constant, then it has no variability, and the correlation would necessarily equal zero. the graph would just be a line.
2. if a symmetrical pattern in all directions from the center were found. <>

Front 4

inverse relationships

Back 4

a coefficient preceded by a negative sign. as one variable increases the other decreases. to the right and down.

Front 5

curvilinear relationships

Back 5

correlations can show curves in the data. there may be an inflection or other things.

Front 6

first a correlation study starts with a
2.
3.
4.
5.

Back 6

hypothesis
2. gather data on two things
3. consider other influences of other variables
4. check the assumptions that underlie the correlation
5. provide evidence that the assumptions underlying the stat test can be satisfied

Front 7

line of regression

Back 7

a line that could be drawn through all of the points that would show the general relationship that exists. represents the minimum possible distance of the line from the data points.

Front 8

the intercept

Back 8

part of the "best fit" or "line of regression" line. where the line extends into the vertical or y axis. thus, this is the expected value of the dependent variable when the value of the independent variable is zero.

Front 9

slope

Back 9

slope of the best fit line is its angle. direct correlation is a positive slope. an inverse relationship is indicated by a negative slope.

Front 10

correlation does not mean

Back 10

causation

Front 11

a third factor may explain high correlations

Back 11

polio, in summer months, with ice cream sales.. doesnt mean ice cream= polio