In a study of 1006 men in four occupations, a multiple regression was carried out to show how lung function was related to age, smoking and...
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# What is the mean air

capacity of a 20 year old farmworker who smokes 10 cigarettes per day?

What is the estimated difference in air capacity between two farmers of the same age, one of whom smokes 10 cigarettes per day, and the other of whom does not smoke?

Construct a 95% confidence interval for β5. [Note: In R you can get the upper 2.5'th percentile of the t distribution with m degrees of freedom, as qt(.975,m).

Use the Bonferroni procedure to construct simultaneous 95% confidence intervals for β5 and β0.

Construct a 95% confidence interval for the mean of Y , for a 30 year old chemical worker who does not smoke.

Construct a 95% prediction interval for the mean of Y , for a 30 year old chemical worker who does not smoke.

Construct a 95% confidence interval for β0 + β5.

1. In a study of 1006 men in four occupations, a multiple regression was carried
out to show how lung function was related to age, smoking and occupation.
The four occupations represented in the study were physician, firefighter, farm
worker, and chemical worker. The variables in the regression were:
Y air capacity (ml) that the worker can expire in one second
X1 age in years
X2 number of cigarettes smoked per day
X3 1 if chemical worker, 0 otherwise
X4 1 if farm worker, 0 otherwise
X5 1 if firefighter, 0 otherwise
The model Y = Bo + BIX1 + B2X2 + 83X3 + BAX4 + 35X's + e was fit to the
data with the following result:
Y = 4500 - 39X1 - 9X2 - 350X3 - 380X4 - 180X5
It was found that MSE = 9 and
9
8
7
8
3 5 6
1 17
HOTOA
6
1
(X'X)-1 =
5
6
1 6
8
3
7
5
8
8
7
3
5
4

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