In each of Exercises 10.35-10.38, we have provided summary statistics for independent simple random samples from two populations. Preliminary data analyses indicate that the variable under consideration is normally distributed on each population. Decide, in each case, whether use of the pooled t-lest and pooled t-interval procedure is reasonable. Explain your answer.
10.35 x¯1=468.3,s1=38.2,n1=6

x2=394.6,s2=84.7,n2=14

Short Answer

Expert verified

No, that isn't reasonable. Because the sample standard deviations indicate that the two population standard deviations are not identical and the sample sizes are not roughly equal.

Step by step solution

01

Given information

To determine the use of pooled t- test and pooled t- interval test is reasonable with the given sample data.

x¯1=468.3,s1=38.2,n1=6
x2=394.6,s2=84.7,n2=14

02

Explanation

For comparing two population means, the following assumptions are made when using the pooled ttest and pooled t - interval test.
1.) Simple random variables
2.) Independent samples
3) Normal population or large samples.

Note that: In the case of large samples, this pooled t- test is resilient to moderate violation.
4.) Equal population standard deviation.

Note that: In the case of nearly equal sample sizes, this pooled t- test is robust for modest violation.
Assumptions 1and 2 are correct based on the information provided.
Assumption 3 is also confirmed because two populations are regularly distributed.
Yet, there is a significant difference in standard deviation between the two populations.
s1=38.2and s2=84.7.
Assumption 4 is violates.
As a result, Not reasonable.
Because the sample standard deviations indicate that the two population standard deviations are not identical and the sample sizes are not roughly equal.

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Most popular questions from this chapter

Discuss the basic strategy for performing a hypothesis test to compare the means of two populations, based on independent samples.

A variable of two population has a mean of 7.9and standard deviation of 5.4for one of the population and a mean of 7.1and a standard deviation of 4.6 for the other population.

a. For independent samples of sizes 3and6respectively find the mean and standard deviation of x1-x2

b. Must the variable under consideration be normally distributed on each of the two population for you to answer part (a) ? Explain your answer.

b. Can you conclude that the variable x1-x2is normally distributed? Explain your answer.

Identify the assumption for using the two means ztest and the two mean zinterval procedure that renders those procedures generally impractical.

Left-Tailed Hypothesis Tests and CIs. If the assumptions for a pooled t-interval are satisfied, the formula for a (1-α)-level upper confidence bound for the difference, μ1-μ2, between two population means is

x¯1-x~2+ta·Sp1/n1+1/n2

For a left-tailed hypothesis test at the significance level α, the null hypothesis H0:μ1=μ2will be rejected in favor of the alternative hypothesis Ha:μ1<μ2if and only if the (1-α)-level upper confidence bound for μ1-μ2is less than or equal to 0. In each case, illustrate the preceding relationship by obtaining the appropriate upper confidence bound and comparing the result to the conclusion of the hypothesis test in the specified exercise.

a. Exercise 10.45

b. Exercise 10.46

In each of Exercises 10.35-10.38, we have provided summary statistics for independent simple random samples from two populations. Preliminary data analyses indicate that the variable under consideration is normally distributed on each population. Decide, in each case, whether use of the pooled t-lest and pooled t-interval procedure is reasonable. Explain your answer.

10.36 x¯1=115.1,s1=79.4,n1=51
x¯2=24.3,s2=10.5,n2=19

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