A clinical trial was conducted to evaluate the efficacy of a new drug to increase HDL cholesterol (the "good" cholesterol). 80 patients were enrolled in the trial and randomized to receive either the new drug or a placebo. Subjects were instructed to take the assigned medication for 8 weeks at which time their HDL cholesterol was measured again. Descriptive statistics (mean \( \pm S D \) ), reported for the experimental group ( \( n=40 \) ) was \( 40.83 \pm 2.44 \mathrm{mg} / \mathrm{dl} \). Meanwhile, the results for the control group ( \( n=40 \) ) were: \( 41.6 \pm 2.32 \) \( \mathrm{mg} / \mathrm{dl} \). Is there a difference between the health outcomes in the two groups?
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First, we need to understand that we are comparing the means of two independent groups. Therefore, we will use a two-sample t-test to determine if there is a significant difference between the two groups. Show more…
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I am interested in determining if a new drug is effective at reducing cholesterol in adults. 100 randomly selected adults had the cholesterol measured prior to the beginning of the study and again after taking the new medication for 30 days. The researchers were interested in determining if the average cholesterol levels were decreased significantly over the 30-day period. How would you recommend they analyze the results? Group of answer choices Use a paired analysis to compare the average before and after cholesterol readings. Use an independent analysis to compare the average before and after cholesterol readings. Compare the variation of the before and after cholesterol readings using a Folded F-test Compare the two population proportions using an independent sampling approach
Marc L.
A better drug? In a pilot study, a company’s new cholesterol-reducing drug outperforms the currently available drug. If the data provide convincing evidence that the mean cholesterol reduction with the new drug is more than 10 milligrams per deciliter of blood (mg/dl) greater than with the current drug, the company will begin the expensive process of mass-producing the new drug. For the 14 subjects who were assigned at random to the current drug, the mean cholesterol reduction was 54.1 $\mathrm{mg/dl}$ with a standard deviation of 13.3 $\mathrm{mg} / \mathrm{dl}$ . Graphs of the data reveal no outliers or strong skewness. (a) Carry out an appropriate significance test. What conclusion would you draw? (Note that the null hypothesis is not $H_{0} : \mu_{1}-\mu_{2}=0 .$ ) (b) Based on your conclusion in part (a), could you have made a Type I error or a Type II error? Justify your answer.
Comparing Two Populations or Groups
Comparing Two Means
According to a recent poll, 29% of adults in a certain area have high levels of cholesterol. They report that such elevated levels "could be financially devastating to the regions healthcare system" and are a major concern to health insurance providers. Assume the standard deviation from the recent studies is accurate and known. According to recent studies, cholesterol levels in healthy adults from the area average about 205 mg/dL, with a standard deviation of about 35 mg/dL, and are roughly Normally distributed.If the cholesterol levels of a sample of 45 healthy adults from the region is taken, answer part c (c) What is the probability that the mean cholesterol level of the sample will be less than 195?
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