Q1: n a test of the effectiveness of garlic for lowering cholesterol,

45

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

(beforeafter)

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

3.1

and a standard deviation of

19.6.

Construct a

99%

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 LDL cholesterol?

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Part 1

What is the confidence interval estimate of the population mean

?

enter your response here

mg/dL<

mg/dL

(Round to two decimal places as needed.)

Q2: An IQ test is designed so that the mean is 100 and the standard deviation is

13

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

90%

confidence that the sample mean is within

6

IQ points of the true mean. Assume that

=13

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

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Part 1

The required sample size is

enter your response here.

(Round up to the nearest integer.)

Q3: Salaries of

42

college graduates who took a statistics course in college have a mean,

x,

of

$64,000.

Assuming a standard deviation,

,

of

$11,217,

construct a

99%

confidence interval for estimating the population mean

.

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Part 1

$enter your response here<<$enter your response here

(Round to the nearest integer as needed.)