PS 8 full - ECON 2843 Problem Set 8 1. Problem 9.6 in...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
ECON 2843 Problem Set 8 1. Problem 9.6 in Newbold on p. 323. A company which receives shipments of batteries tests a random sample of nine of them before agreeing to take a shipment. The company is concerned that the true mean lifetime for all batteries in the shipment should be at least 50 hours. From past experience, it is safe to conclude that the population distribution of lifetimes is normal, with standard deviation 3 hours. For one particular shipment, the mean lifetime for a sample of nine batteries was 48.2 hours. Test at the 10% level the null hypothesis that the population mean lifetime is a least 50 hours. 2. Problem 9.7 in Newbold on p. 323. A pharmaceutical manufacturer is concerned about the impurity concentration in pills, and it is anxious that this concentration does not exceed 3%. It is known that from a particular production run, impurity concentrations follow a normal distribution with standard deviation .4%. ; A random sample of 64 pills from a production run was checked, and the sample mean impurity concentration was found to be 3.07%. a. Test at the 5% level the null hypothesis that the population mean impurity concentration is 3% against the alternative that it is more than 3%. b. Find the p-value for this test. c. Suppose that the alternative hypothesis had been two-sided rather than one- sided (with null hypothesis H 0 : μ = 3). State, without doing the calculations, whether the p-value of the test would be higher than, lower than, or the same as that found in part (b). Sketch a graph to illustrate your reasoning. d. In the context of this problem, explain why a one-sided alternative hypothesis is more appropriate than a two-sided alternative. 3.
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/07/2008 for the course ECON 2843 taught by Professor Hudgins during the Spring '08 term at The University of Oklahoma.

Page1 / 3

PS 8 full - ECON 2843 Problem Set 8 1. Problem 9.6 in...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online