CEE 110 PS5 11 Solutions

# CEE 110 PS5 11 Solutions - UNIVERSITY OF CALIFORNIA LOS...

This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

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

Unformatted text preview: UNIVERSITY OF CALIFORNIA, LOS ANGELES Civil and Environmental Engineering Department CEE 110 Introduction to Probability and Statistics for Engineers Spring Quarter 2011 MW 12-2 PM Franz 1178 Prof. K. D. Stolzenbach 5732J Boelter Hall, 206-7624 [email protected] Problem Set 5 Solutions _____________________________________________________________________________ 1. a) 95% Two-sided CI on the true mean life of a 75-watt light bulb For α = 0.05, zα/2 = z0.025 = 1.96 , and x = 1014, σ =25 , n=20 b) 95% One-sided CI on the true mean piston ring diameter For α = 0.05, zα = z0.05 =1.65 and x = 1014, σ =25 , n=20 The lower bound of the one sided confidence interval is higher than the lower bound of the two-sided confidence interval even though the level of significance is the same. This is because all of the Type I probability (or α) is in the left tail (or in the lower bound). 2. 95% Confident that the error of estimating the true mean life of a 75-watt light bulb is less than 5 hours. For α = 0.05, zα/2 = z0.025 = 1.96 , and σ =25 , E=5 Always round up to the next number, therefore n = 97 3. 99% lower confidence bound on mean Izod impact strength 4. 90% CI on the mean frequency of a beam subjected to loads 5. a) 95% Confidence Interval on the death rate from lung cancer. b) E = 0.03, α = 0.05, zα/2 = z0.025 = 1.96 and = 0.823 as the initial estimate of p, , n ≅ 622. c) E = 0.03, α = 0.05, zα/2 = z0.025 = 1.96 at least 95% confident , n ≅ 1068. 6. a) 95% Confidence Interval on the true proportion of helmets showing damage b) c) 7. ...
View Full Document

{[ snackBarMessage ]}

### Page1 / 3

CEE 110 PS5 11 Solutions - UNIVERSITY OF CALIFORNIA LOS...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online