Question

1. A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before​ treatment, 25 subjects had a mean wake time of 105.0 min. After​ treatment, the 25 subjects had a mean wake time of 84.2 min and a standard deviation of 22.5 min. Assume that the 25 sample values appear to be from a normally distributed population and construct a 95​% confidence interval estimate of the mean wake time for a population with drug treatments. What does the result suggest about the mean wake time of 105.0 min before the​ treatment? Does the drug appear to be​ effective?

Construct the 95​% confidence interval estimate of the mean wake time for a population with the treatment. Round to one decimal place as​ needed.

2. In a study of speed​ dating, male subjects were asked to rate the attractiveness of their female​ dates, and a sample of the results is listed below ​(1=not ​attractive; 10=extremely ​attractive). Construct a confidence interval using a 99​% confidence level. What do the results tell about the mean attractiveness ratings of the population of all adult​ females?

5​, 7​, 2​, 8​, 6​, 5​, 7​, 9​, 8​, 8​, 6​,9

What is the confidence interval for the population mean μ​? Round to one decimal place as​ needed.

3. A food safety guideline is that the mercury in fish should be below 1 part per million​ (ppm). Listed below are the amounts of mercury​ (ppm) found in tuna sushi sampled at different stores in a major city. Construct a 98​% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tuna​ sushi? 0.55 ,0.78, 0.10 , 0.91,  1.25 , 0.54, 0.79

What is the confidence interval estimate of the population mean μ​? Round to three decimal places as​ needed.

4. Listed below are the amounts of net worth​ (in millions of​ dollars) of the ten wealthiest celebrities in a country. Construct a 95​% confidence interval. What does the result tell us about the population of all​ celebrities? Do the data appear to be from a normally distributed population as​ required? 245, 194, 182, 172, 153, 153, 145, 145, 145, 145

What is the confidence interval estimate of the population mean μ​? Round to one decimal place as​ needed.

I need help on these 4 questions. Thank you

Answer 1

1:

Since confidence interval does not contain 105.0 min and values are less than 105.0 so interval suggest that mean wake time is less than 105.0 mins. The drug appears to be​ effective.

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2:

First we need to find the mean and SD of data set. Following table shows the calculations:

	X	(X-mean)^2
	5	2.7889
	7	0.1089
	2	21.8089
	8	1.7689
	6	0.4489
	5	2.7889
	7	0.1089
	9	5.4289
	8	1.7689
	8	1.7689
	6	0.4489
	9	5.4289
Total	80	44.6668

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