Math Snap
PROBLEM
Suppose that you run a correlation and find the correlation coefficient is 0.325 and the regression equation is . The centroid of your data was .
If the critical value is .632 , use the appropriate method to predict the value when is 3.9
STEP 1
What is this asking?
Given a regression equation, correlation coefficient, critical value, and centroid, predict the y-value for a specific x-value.
Watch out!
Don't forget to consider the critical value when deciding whether to use the regression equation or the mean y-value from the centroid for prediction!
STEP 2
1. Compare the correlation coefficient and the critical value.
2. Predict the y-value.
STEP 3
The absolute value of the correlation coefficient is .
This tells us the strength of the linear relationship between x and y.
STEP 4
We're given a critical value of .
Since is less than , the correlation is not statistically significant.
This means we shouldn't use the regression equation for prediction!
STEP 5
Since the correlation isn't significant, the best prediction for any x-value is simply the average y-value, which is given by the y-coordinate of the centroid.
Our centroid is , so the mean y-value is **.
STEP 6
Therefore, when , our predicted y-value is .
SOLUTION
The predicted y-value when is .