In: Statistics and Probability
In a multiple linear regression with 40 observations, the
following sample regression equation is obtained:
yˆy^ = 12.5 + 2.4x1 − 1.0x2
with se = 5.41. Also, when
x1 equals 16 and x2 equals
5, se(yˆ0)se(y^0) = 2.60.
[You may find it useful to reference the t
table.]
a. Construct the 95% confidence interval for
E(y) if x1 equals 16 and
x2 equals 5. (Round intermediate
calculations to at least 4 decimal places,
"tα/2,df" value to 3 decimal places, and final
answers to 2 decimal places.)
b. Construct the 95% prediction interval for
y if x1 equals 16 and
x2 equals 5. (Round intermediate
calculations to at least 4 decimal places,
"tα/2,df" value to 3 decimal places, and final
answers to 2 decimal places.)
c. Which interval is wider?
Confidence interval since it does not include the variability caused by the error term.
Prediction interval since it includes the variability caused by the error term.
Confidence interval since it includes the variability caused by the error term.
Prediction interval since it does not include the variability caused by the error term.