The one-sample t statistic from a sample of n =25 observations for the two-sided test of

H0:μ=64Hd:μ64

has the value t =- 1.12.

(a) Find the P-value for this test using (i) Table B and (ii) your calculator. What conclusion would you draw at the 5% significance level? At the 1% significance level?

(b) Redo part (a) using an alternative hypothesis of Ha:μ<64

Short Answer

Expert verified

a. p-value is0.2738

b. p-value is0.1369

Step by step solution

01

Introduction

The scientific strategy requires that one can test it. Scientists for the most part base scientific speculations on previous observations that can't satisfactorily be explained with the available scientific theories

02

Explanation Part (a)

The hypotheses are,

H0:μ=64Ha:μ64

calculating the degree of freedom,

Df=n1=25-1=24

Using a calculator the p-value is found to be0.136

For the two-sided test p-value is=2×0.1369=0.2738

localid="1654666340202" 0.2738>(α=0.01andα=0.05)

Hence the p-value is 0.2738and as it is greater than the significance levels the null hypothesis is not rejected.

03

Explanation Part (b)

The hypotheses,

H0:μ=64Ha:μ<64

Calculating the p-value for one-tailed test,

localid="1654666370875" =P(t>∣t|)=P(t>|1.12|)=0.1369

Hence the p-value is 0.1369and as it is greater than the significance levels the null hypothesis is not rejected.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

To determine the reliability of experts who interpret lie detector tests in criminal investigations, a random sample of 280such cases was studied. The results were

(a) 15/280.

(b) 9/280.

(c) 15/140.

(d) 9/140.

(e) 15/146.

Improving health A large company's medical director launches a health promotion campaign to encourage employees to exercise more and eat better foods. One measure of the effectiveness of such a program is a drop in blood pressure. The director chooses a random sample of 50employees and compares their blood pressures from physical cams given before the campaign and again a year later. The mean change (after - before) in systolic blood pressure for these 50employees is -6and the standard deviation is 19.8.

(a) Do these data provide convincing evidence of an average decrease in blood pressure among all of the company's employees during this year? Carry out a test at the α=0.05significance level.

(b) Can we conclude that the health campaign caused a decrease in blood pressure? Why or why not?

In a test of H0:p=0.4against Ha:p0.4, a random sample of size 100yields a test statistic of z=1.28. The P-value of the test is approximately equal to

(a) 0.90.

(b) 0.40.

(c) 0.05.

(d) 0.20.

(e) 0.10.

Refer to Exercise 79. Construct and interpret a 95%confidence interval for the population mean M. What additional information does the confidence interval provide .

Taking stock An investor with a stock portfolio worth several hundred thousand dollars sued his broker due to the low returns he got from the portfolio at a time when the stock market did well overall. The investor’s lawyer wants to compare the broker’s performance against the market as a whole. He collects data on the broker’s returns for a random sample of36weeks. Over the 10-year period that the broker has managed portfolios, stocks in the Standard & Poor’s 500index gained an average of 0.95%per month. The Minitab output below displays descriptive statistics for these data, along

with the results of a significance test.

(a) Determine whether there are any outliers. Show your work.

(b) Interpret the P-value in context.

(c) Do these data give convincing evidence to support the lawyer’s case? Carry out a test to help you answer this question.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free