For this assignment, you will be required to read Sullivan's (2008) Essentials of Biostatistics Workbook: Statistical Computing Using Excel. Please save your results as a 97/2003 Excel file. Answers should be in the same workbook and 5.1 practice problems on Worksheet 1, 6.6 problems on Worksheet 2 and 7.9 Practice Problems on worksheet 3. Highlight the answers.
5.1 Practice Problems (Worksheet 1)
1. Total cholesterol in children aged 10-15 is assumed to follow a normal distribution with a mean of 191 and a standard deviation of 22.4.
a. What proportion of children 10-15 years of age have total cholesterol between 180 and 190?
b. What proportion of children 10-15 years of age would be classified as hyperlipidemic (Assume that hyperlipidemia is defined as a total cholesterol level over 200)?
c. What is the 90th percentile of cholesterol?
2. Among coffee drinkers, men drink a mean of 3.2 cups per day with a standard deviation of 0.8 cups. Assume the number of coffee drinks per day follows a normal distribution.
a. What proportion drink 2 cups per day or more?
b. What proportion drink no more than 4 cups per day?
c. If the top 5% of coffee drinkers are considered heavy coffee drinkers, what is the minimum number of cups consumed by a heavy coffee drinker? Hint: Find the 95th percentile.
6.6 Practice Problems (Worksheet 2)
3. A study is run to estimate the mean total cholesterol level in children 2-6 years of age. A sample of 9 participants is selected and their total cholesterol levels are measured as follows.
185 225 240 196 175 180 194 147 223
Generate a 95% confidence interval for the true mean total cholesterol levels in adults with a history of hypertension.
7.9 Practice Problems (Worksheet 3)
1. The following data were collected in a clinical trial evaluating a new compound designed to improve wound healing in trauma patients. The new compound was compared against a placebo. After treatment for 5 days with the new compound or placebo the extent of wound healing was measured and the data are shown below.
Percent Wound Healing
Treatment 0-25% 26-50% 51-75% 76-100%
New Compound (n=125) 15 37 32 41
Placebo (n=125) 36 45 34 10
Is there a difference in the extent of wound healing by treatment? (Hint: Are treatment and the percent wound healing independent?) Run the appropriate test at a 5% level of significance.