PRACTICE WORKSHEET 2
|1. Review the following descriptions and state whether the description is an observationalor experimental study:|
a. A random sample of 100 ISUstaff wasrandomly assigned to either a traditional safety program or a non-traditional safety-training program. After training, both groups returned to work. Costs associated with injury claims and lost time were recorded for both groups and compared.
b. The grades of one hundred 12th graders undergoing weekly tutoring classes were compared with grades of one hundred 12th graders who were not participating in the weekly tutoring classes at Terre Haute High School. Inferences about the effectiveness of the tutoring classes were made after the study.
- A confounder is a third variable that can make it appear (sometimes incorrectly) that an observed exposure is associated with an outcome.True/False.
- Which of the following is not an example of bias that an investigator should guard against?
- Selection bias Investigator bias c. Subject bias d. Preparation bias
- Fat content was measured in a sample of sandwiches served at various local fast food restaurants. The total fat content (in grams) is listed as follows: 10, 15, 25, 15, 20, 21, 23, 24, 19, and 10. Calculate the mean, median, and modefor the data set.
- The HDL measurements for a sample of professional males are as follows: 31, 42, 21, 28, 30,46, and 50. Using these measurements, calculate therange,IQR (Interquartile Range), variance, and standard deviation of the data set.
- The sugar intakes (in teaspoons) for a sample of adolescent females were the following: 11, 14, 13, 18, 16, 19, 19, 20, 21, 22, 20, 23, 26, 26, 28, 25, 32, 30, 31, 34, and 31. Using the sugar intake values above, complete the frequency table below:
|Class Interval||Frequency||Relative Frequency||Cumulative Relative Frequency|