Suppose a simple linear regression is used to examine the relationship between marathon completion time (minutes) and age (years) for 12 subjects:

DataMean

VarianceAge (X)

20, 24, 32, 33, 36, 42, 48, 50, 55, 61, 62, 71

44.5256.45Completion Time (Y)

195, 184, 202, 200, 223, 243, 219, 230, 270, 230, 255, 260

225.9753.5

That is, the model, timei=

0

0+

1

1agei+

iis estimated where,

0

=160.63

^0=160.63and

1

=1.47

^1=1.47. Further suppose that the estimated residual variance,

2

=221.8

se2=221.8.

1.

What is the expected marathon completion time at age 50?

a.

234.1 minutes

b.

160.8 minutes

c.

243.3 minutes

d.

118.2 minutes

2.The 95% confidence interval for the mean marathon time of individuals of age 50 is approximately:

a.

(225.0, 243.0) minutes

b.

(224.0, 244.0) minutes

c.

(199.4, 268.8) minutes

d.

(203.5, 264.5) minutes

e.

None of the above answers are correct.

I only need the answer don't need the experience! thank you