Refer to Exercise 11.28.
(a) What proportion of y variability is explained by the linear regression on x?
(b) Find the sample correlation coefficient.
Exercise 11.28
An engineer found that by adding small amounts of a compound to rechargeable batteries during manufacture, she could extend their lifetimes. She experimented with different amounts of the additive (g) and measured the hours they lasted in a laptop.
Amount Life
of Additive (hours)
0.................... 3.9
1.................... 4.0
2.................... 4.5
3.................... 4.6
4.................... 5.0

(b) TestH0:β1, = 1 versus H1,: β1 # 1 with a = .05.
(c) Estimate the expected y value corresponding to x = 3.5 and give a 95% confidence interval. Interpret.
(d) Construct a 90% confidence interval for the intercept β0. Interpret.

Transcribed Image Text:

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