Question from the curriculum:

Selected Regression Output - Dependent Variable: Amtex Share Return Intercept 0.0095 ( coefficient ); 0.0078 ( standard error) Oil return 0.2354 ( coefficient ); 0.0760 ( standard error) ( Note: The critical t-value for a one-sided t-test at the 5% significance level is 1.691)

- Vasileva should compute the: A coefficient of determination to be 0.4689. B 95% confidence interval for the intercept to be –0.0037 to 0.0227. C 95% confidence interval for the slope coefficient to be 0.0810 to 0.3898.

The correct answer is C while I got B because I have used a df of 35 ( 36 total number of observations) and significance level of 5% ( t= 1.691 as shown above).

Thus, I did this for the confidence interval: 0.0095+ 1.691 ( 0.0078) = 0.22682 ( upper level) and 0.0095-1.691 (0.0078)= -0.003682 (lower level)

C is correct. The confidence interval for the slope coefficient is calculated as: Where b1 0.2354, sb1= 0.0760 and tc = 2.032

The lower limit for the confidence interval = 0.2354 – (2.032 × 0.0760) = 0.0810 The upper limit for the confidence interval = 0.2354 + (2.032 × 0.0760) = 0.3898

I don’t get it ; where is this 2.032 coming from and why are they not using 1.691 if it was given?