Question

Refer to the accompanying data display that results from a sample of airport data speeds in Mbps. Complete parts​ (a) through​ (c) below.	TInterval
	​(13.046,22.15) x overbarxequals=17.598 Sxequals=16.01712719 nequals=50

a. Express the confidence interval in the format that uses the​ "less than" symbol. Given that the original listed data use one decimal​ place, round the confidence interval limits accordingly.

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a. Express the confidence interval in the format that uses the​ "less than" symbol. Given that the original listed data use one decimal​ place, round the confidence interval limits accordingly. 13.05 Mbpsless thanmuless than 22.15 Mbps ​(Round to two decimal places as​ needed.) b. Identify the best point estimate of mu and the margin of error. The point estimate of mu is 17.60 Mbps. ​(Round to two decimal places as​ needed.) The margin of error is Eequals 4.55 Mbps. ​(Round to two decimal places as​ needed.) c. In constructing the confidence interval estimate of mu​, why is it not necessary to confirm that the sample data appear to be from a population with a normal​ distribution? A. Because the sample size of 50 is greater than​ 30, the distribution of sample means can be treated as a normal distribution. Your answer is correct.B. Because the sample is a random​ sample, the distribution of sample means can be treated as a normal distribution. C. Because the sample standard deviation is​ known, the normal distribution can be used to construct the confidence interval. D. Because the population standard deviation is​ known, the normal distribution can be used to construct the confidence interval.

Answer 1

a.

The confidence interval is 13.05 Mbps 22.15 Mbps ​

b.

The point estimate of mu is 17.60 Mbps. ​

The margin of error is E = (22.15 - 13.046) / 2 =  4.55 Mbps. ​

c.

It not necessary to confirm that the sample data appear to be from a population with a normal​ distribution

A. Because the sample size of 50 is greater than​ 30, the distribution of sample means can be treated as a normal distribution.