Statistics

Statistics

The 2nd step in regression analysis is to determine the intercept: We can substitute the calculated slope into the intercept formula.

∑ − (∑ )

30 − 2(60) 5

90 5

=

=

= −

= −18

The 3rd step, now that we know the slope and intercept, we can use these values in regression equation formula.

= + = −18 + 2

If we want to know the approximate y value is we are given = 15 . Then we can substitute the value in the above equation and solve for .

= −18 + 2(15) = −18 + 30 = 12

*Tip: Remember to use order of operations when solving for slope and intercept.

3.3 Correlation Analysis

Correlation is used to determine the effect. For example, how does change with ; or, how does the dependent variable change when the independent variable changes. From this information, we can determine relationships.

Let’s look at an example.

Y-axis

X-axis

From this linear example, we are looking into the correlation of (independent variable) on (dependent variable). This is true for all graphs, and you should remember the location of the -axis and -axis. We can see that as increases, increases. Let’s put some values to our graph:

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