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STAT chapt 3
Question | Answer |
---|---|
cross–tabulation table | an arrangement of data in a two–way classification. |
input variable | the variable we know or can control. |
least squares criterion | requires finding the constants b0 (y–intercept) and b1 (slope) such that the sum of the squares of observed minus predicted values is as small as possible. |
line of best fit | a line whose equation represents the smallest possible differences between the squares of observed minus predicted values on a line |
linear correlation | the strength of a linear relationship between two variables, determined by the preciseness of shift in y as x increases. |
linear regression | the straight line that best describes the relationship between two variables |
lurking variable | a variable that is not included in a study but has an effect on the variables of the study and makes it appear that those variables are related. |
negative correlation | a correlation in which an increase in x leads to a decrease in y. |
ordered pairs | a mathematical expression (x, y) where x is the input variable written first, and y is the output variable written second. |
output (dependent) variable | the predicted variable. |
Pearson’s product moment formula | the formula that determines the coefficient of linear correlation (r). |
positive correlation | a correlation in which an increase in x leads to an increase in y. |
predicted value | the value of y calculated by modeling a particular value of x with a prediction equation. |
prediction equation | an equation that models a mathematical relationship between x and y with an algebraic expression. Examples of prediction equations include linear (straight–line), quadratic, exponential, and logarithmic. |
regression | the algebraic expression that describes the relationship between two variables |
regression analysis | finds the equation of the line that best describes the relationship between the two variables under examination. That is, regression analysis describes the mathematical relationship between the two variables. |
scatter diagram | a plot of all the ordered pairs of bivariate data on a coordinate axis system. |
slope, b1 | the ratio of the rise over the run (horizontal distance) of a line. In the equation for a line of best fit, the slope is denoted b1. |