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Chapter 10: Q. 44 (page 666)

Mary was interested in comparing the mean word length in articles from a medical journal and an airline鈥檚 in-flight magazine. She counted the number of letters in the first 400words of an article in the medical journal and in the first 100words of an article in the airline magazine. Mary then used statistical software to produce the histograms shown.

Let 渭MJ=the true mean length of all words in the medical journal and 渭AM=the true mean length of all words in the airline magazine. Check if the conditions for calculating a confidence interval for渭MJ-渭AM are met.

Short Answer

Expert verified

Random condition is not satisfied.

Step by step solution

01

Step 1. Given information

Given:

02

Step 2. Explanation

We have to check if the conditions are met or not. Therefore,

There are three conditions to be satisfied:

Random: It is not satisfied because the samples are not independent random samples as we conveniently select the first 400words and the first 100words of the two article.

Independent: It is satisfied because the400 words is less than10% of the population of all words in the medical journal and the sample of100 words is less than10% of the population of all words in the airline magazine.

Normal: It is satisfied because the two samples are large and since 100isatleast30and role="math" localid="1664190569522" 400isatleast30.

Thus, all the conditions are not satisfied since random condition is not satisfied and it is not appropriate to determine a confidence interval for the mean difference.

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