COMM 291 ASSIGNMENT 6

E 95 confidence interval for mean when x 20 970133

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: calculation and Excel is just due to round-off error. e) 95% Confidence Interval for Mean when x = 20 ˆ µ = 9701.33 + 1213.45(20) = 33970.33 se2 = 7705.6262 = 59,376,672.05 SE(b1) = 338.10 x-bar = 17 ˆ SE( µ ) = sqrt[(338.102)(20-17)2+7705.6262/25] = 1844.96 t*(23 df) = 2.069 95% CI: 33,970.33 ± 2.069(1844.96) = 33,970.33 ± 3817.22 or ($30,153.11 ,$37,787.55) f) 90% Prediction Interval when x = 20. ˆ y = 9701.33 + 1213.45(20) = 33970.33 se2 = 7705.6262 = 59,376,672.05 SE(b1) = 338.10 x-bar = 17 ˆ SE( y ) = sqrt[(338.102)(20-17)2+7705.6262/25+ 7705.6262] = 7923.42 t*(23 df) = 1.714 (remember that 90% was asked for) 90% PI: 33,970.33 ± 1.714(7923.42) = 33,970.33 ± 13,580.74 or ($20,389.59,$47,551.07) Upper Bound: $47,551 Note: Round-off errors will occur in e) and f) if the Excel values of t*(23) are used. Extra: Residual plot and Normal Probability plot confirm that the assumptions are reasonable. Question 2: Modeling PGA Golfers' Success a) Here is the output from fitting a regression model t...
View Full Document

This note was uploaded on 01/16/2014 for the course COMM 291 taught by Professor E.fowler during the Fall '10 term at UBC.

Ask a homework question - tutors are online