The following table shows, for eight vintages of select wine, purchases per buyer (y) and the wine buyer’s rating in a year (x): x 3.6 3.3 2.8 2.6 2.7 2.9 2.0 2.6 y 24  21  22  22 18  13   9   6 a. Estimate the regression of purchases per buyer on the buyer’s rating. b. Interpret the slope of the estimated regression line. c. Find and interpret the coefficient of determination.d. Find and interpret a 90% confidence interval for the slope of the population regression line. e. Find a 90% confidence interval for expected purchases per buyer for a vintage for which the buyer’s rating is 2.0.

Calculus For The Life Sciences
2nd Edition
ISBN:9780321964038
Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Chapter1: Functions
Section1.EA: Extended Application Using Extrapolation To Predict Life Expectancy
Problem 2EA
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The following table shows, for eight vintages of select wine, purchases per buyer (y) and the wine buyer’s rating in a year (x):
x 3.6 3.3 2.8 2.6 2.7 2.9 2.0 2.6
y 24  21  22  22 18  13   9   6
a. Estimate the regression of purchases per buyer on the buyer’s rating.
b. Interpret the slope of the estimated regression line.
c. Find and interpret the coefficient of determination.
d. Find and interpret a 90% confidence interval for the slope of the population regression line.
e. Find a 90% confidence interval for expected purchases per buyer for a vintage for which the buyer’s rating is 2.0.

Expert Solution
Step 1

“Since you have posted a question with multiple sub-parts, we will solve first three subparts for you. To get the remaining sub-parts solved, please repost the complete question and mention the sub-parts to be solved.”

Given

The data is as follows:

x y
3.6 24
3.3 21
2.8 22
2.6 22
2.7 18
2.9 13
2 9
2.6 6
Step 2
  x y x*y x^2 y^2
  3.6 24 86.4 12.96 576
  3.3 21 69.3 10.89 441
  2.8 22 61.6 7.84 484
  2.6 22 57.2 6.76 484
  2.7 18 48.6 7.29 324
  2.9 13 37.7 8.41 169
  2 9 18 4 81
  2.6 6 15.6 6.76 36
Sum 22.5 135 394.4 64.91 2595

 

a.

x¯=i=1nxin=22.58=2.8125

y¯=i=1nyin=1358=16.875

SSXX=i=1nxi2-1n×i=1nxi2=64.91-22.528=1.62875

SSYY=i=1nyi2-1n×i=1nyi2=2595-13528=316.875

SSXY=i=1nxiyi-1ni=1nxii=1nyi=394.4-22.5×1358=14.7125

β1=SSXYSSXX=14.71251.62875=9.033

β0=y¯-x¯×β1=16.875-2.8125×9.033=-8.5303

The regression equation is as follows:

y=β0+β1xy=-8.5303+9.033x

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