Question

Researchers are conducting a study in an attempt to establish a linear relationship between the number of online music video views and the number of guitar sales. A computer output for regression is shown and is based on a sample of seven observations. Predictor Coeff St. Dev t Ratio p-Value Constant 7.85671094 1.316226455 5.969118 0.001889 Music Video Views 0.094781123 0.027926367 3.393965 0.019378 What represents the 99% confidence interval for the slope of the regression line?

a. 0.0948 ± 3.499(1.3162)

b. 0.0948 ± 4.032(1.3162)

c. 0.0948 ± 3.707(0.0279)

d. 0.0948 ± 4.032(0.0279)

Answer 1

d. 0.0948 ± 4.032(0.0279)

Explanation:

A 99% confidence interval for the coefficient of promotional expenditures is, First, compute the t critical value then find confidence interval.

The t critical value for the 99% confidence interval is,

The sample size is small and two-tailed test. Look in the column headed es = 0.01 and the row headed in the t distribution table by using degree of freedom is here

for (n-2=5) degree of freedom and 99% confidence ; critical t =4.032

therefore 99% confidence interval for the slope =estimated slope -/+ t*Std error

= 0.094781123 -/+ 4.032* 0.027926367 = -0.017822 to 0.207384