Tut sol week13

# Tut sol week13 - BES Tutorial Sample Solutions S1/10 WEEK...

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

1 BES Tutorial Sample Solutions, S1/10 WEEK 13 TUTORIAL EXERCISES (To be discussed in the week starting May 31) 1. It is claimed by a manufacturer that its new type of light bulb is subject to less variability of bulb life. It is known that the former bulb type had a standard deviation of life of 150 hours. To test this claim, a consumer organization takes a sample of 41 of these new bulbs and measures their lives, finding a standard deviation of bulb life of 140 hours. Assuming light bulb lives are approximately normally distributed, test the manufacturer’s claim at a 5% level of significance. n = 41, s = 140 ܪ ൌ 150 ; ܪ ൏ 150 Under ܪ ሺ݊െ1ሻݏ ߪ 40 ൈ ݏ 150 ସଵିଵ Decision rule: Reject ܪ if ݈ܿܽܿݑ݈ܽݐ݁݀ ߯ ൏߯ ଴.ଽହ,ସ଴ ൌ 26.5093 Since calculated ߯ 40 ൈ 140 150 ൌ 34.84 ൐ ߯ ଴.ଽହ,ସ଴ ൌ 26.5093 we do not reject ܪ and conclude that the manufacturer’s claim of lower bulb life variability is not supported by the data.

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

View Full Document
2 2.
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 09/22/2011 for the course ECON 1203 taught by Professor Denzilgfiebig during the Three '11 term at University of New South Wales.

### Page1 / 5

Tut sol week13 - BES Tutorial Sample Solutions S1/10 WEEK...

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

View Full Document
Ask a homework question - tutors are online