A study was conducted to establish the average level of total serum cholesterol in a group of patients with acute coronary syndrome. The study results were reported separately for males and females. The mean total cholesterol level was 230 mg/dL for males and 220 mg/dL for females. Which of the following is the best statistical method to compare the average cholesterol level for males and females?

Question

A study was conducted to establish the average level of total serum cholesterol in a group of patients with acute coronary syndrome.  The study results were reported separately for males and females.  The mean total cholesterol level was 230 mg/dL for males and 220 mg/dL for females.  Which of the following is the best statistical method to compare the average cholesterol level for males and females?

Quizplus · Accepted Answer

The two-sample t test is commonly employed to compare two means. Several statistical approaches can be used, but the basic requirements needed to perform this test are the two mean values, the sample variances, and the sample size. The t statistic is then obtained to calculate the p value. If the 'p' value is less than 0.05, the null hypothesis (that there is no difference between two groups) is rejected, and the two means are assumed to be statistically different. If the 'p' value is large, the null hypothesis is retained. (Choice B) The two-sample z test can also be used to compare two means, but population (not sample) variances are employed in the calculations. Because population variances are not usually known, the test has limited applicability. (Choice C) The ANOVA (i.e., analysis of variance) is used to compare three or more means. (Choice D) The chi-square test is appropriate for categorical data and proportions. (Choice E) Meta-analysis is an epidemiologic method of pooling the data from several studies to do an analysis having a relatively big statistical power. Educational Objective: The two-sample t test is a statistical method that is commonly employed to compare the means of two groups of subjects.

A Study Was Conducted to Establish the Average Level of Total