Fix this statement: Ha : = 0. (Four fixes are possible.) Exercises 14.3 Bicycle helmet use,

Fix this statement: “Ha

: β = 0”. (Four fixes are possible.)

Exercises 14.3 Bicycle helmet use, n = 12. Exercise 14.1 introduced data for a cross-sectional survey of bicycle helmet use in Northern California.

Table 14.5 lists the data. Exercise 14.1

(a) revealed that observation 13 (Los Arboles) was an outlier.

(a) After eliminating the outlier from the data set (n is now equal to 12), calculate least squares regression coefficients a and b.

Interpret these statistics.

(b) Calculate the 95% confidence interval for slope parameter β.

(c) Use the 95% confidence interval to predict whether the slope is significant at α = 0.05.

(d) Optional: Determine the residuals for each of the 12 data points in the analysis. Plot these residuals as a stemplot. Check for major departures from Normality.