In a test of the effectiveness for garlic for lowering chole

In a test of the effectiveness for garlic for lowering cholesterol. 49 subject were treated with garlic in a processed tablet from. Cholesterol levels were measured before and after the treatment. The changes in their leaves of ladle cholesterol (in mg/dl) have a mean of 5.2 and a standard deviation of 15.6 Complete parts (a) and (b) below. Click here to view a distribution table. Click here to view page 1 of the standard normal destruction table. Click here to view page 2 of the standard normal distribution tables. What is the best point estimate of the population mean not change in LDL cholesterol after the garlic treatment? The best point estimate is mg/dl. (Type an integer or a decimal.) Construct a 90% confidence interval estimate of the mean net change LDL cholesterol after garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL cholesterol? What is the confidence interval estimate of the population mean p?

Solution

A)

The point estimate is the sample mean, 5.2. [ANSWER]

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b)

Note that              
Margin of Error E = z(alpha/2) * s / sqrt(n)              
Lower Bound = X - z(alpha/2) * s / sqrt(n)              
Upper Bound = X + z(alpha/2) * s / sqrt(n)              
              
where              
alpha/2 = (1 - confidence level)/2 =    0.05          
X = sample mean =    5.2          
z(alpha/2) = critical z for the confidence interval =    1.644853627          
s = sample standard deviation =    15.6          
n = sample size =    49          
              
Thus,              
Margin of Error E =    3.665673797          
Lower bound =    1.534326203          
Upper bound =    8.865673797          
              
Thus, the confidence interval is              
              
(   1.534326203   ,   8.865673797   ) [ANSWER]

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c)

OPTION D: The confidnece interval limits do not contain 0, suggesting that the garlic treatment did affect the LDL cholesterol levels. [OPTION D]