What formulas do I use and how do I know when to use them? What words in the word problem indicate which formula is appropriate?

1)An IQ test is designed so that the mean is 100 and the standard deviation is 15

15 for the population of normal adults. Find the sample size necessary to estimate the mean IQ score of statistics students such that it can be said with 99

99% confidence that the sample mean is within 6

6 IQ points of the true mean. Assume that sigma

equals

=15

15 and determine the required sample size using technology. Then determine if this is a reasonable sample size for a real world calculation.

2) 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 90

90% confidence interval estimate of the mean amount of mercury in the population. Does it appear that there is too much mercury in tunasushi?

0.54

0.540.72

0.720.09

0.090.97

0.971.31

1.310.52

0.520.95

0.95

What is the confidence interval estimate of the population mean mu

?

nothing

ppmless than

less than

<

nothing

ppm

3) In a test of the effectiveness of garlic for loweringcholesterol, 45

45 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (beforeminus

after) in their levels of LDL cholesterol(in mg/dL) have a mean of 4.6

4.6 and a standard deviation of 18.2

18.2. Construct a 95

95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDLcholesterol?In a test of the effectiveness of garlic for loweringcholesterol, 45

45 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (beforeminus

after) in their levels of LDL cholesterol(in mg/dL) have a mean of 4.6

4.6 and a standard deviation of 18.2

18.2. Construct a 95

95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDLcholesterol? In a test of the effectiveness of garlic for loweringcholesterol, 45

45 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (beforeminus

after) in their levels of LDL cholesterol(in mg/dL) have a mean of 4.6

4.6 and a standard deviation of 18.2

18.2. Construct a 95

95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDLcholesterol? In a test of the effectiveness of garlic for loweringcholesterol, 45

45 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes (beforeminus

after) in their levels of LDL cholesterol(in mg/dL) have a mean of 4.6

4.6 and a standard deviation of 18.2

18.2. Construct a 95

95% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDLcholesterol?