Problem 20E

Bad model? A student who has created a linear model is disappointed to find that her R2 value is a very low 13%.

a) Does this mean that a linear model is not appropriate? Explain.

b) Does this model allow the student to make accurate predictions? Explain.

STAT 2004 WEEK 14 REVIEW: T-test Use a T-test when sigma is unknown. Use cutoffs to test, not p-values. HYPOTHESIS TESTING RATIONALE Make an assumption. Is what you observed likely or unlikely Compare what you observe to what you expect. CHI-SQUARE TEST How different is what we observed from what we expected 2 For each category, calculate (observed−expected) . Add these values expected together for the chi-square value. The degrees of freedom for a chi-square value is the number of categories minus 1. o Look up the actual chi-square value on the table. o Is the ch