PRACTICE WORKSHEET 5
1. Speed, size and strength are thought to be important factors in football performance. The
paper “Physical and Performance Characteristics of NCAA Division I Football Players”
(Research Quarterly for Exercise and Sport (1990): 395-401) reported on physical
characteristics of Division I starting football players in the 1988 football season.
Information for teams ranked in the top 20 was easily obtained, and it was reported that
the mean weight of starters on top-20 teams was 105 kg. A sample of 23 starting players
(various positions were represented) from Division I teams that were not ranked in the
top 20 resulted in a sample mean of 103.3 kg and a sample standard deviation of 16.3 kg.
Is there sufficient evidence to conclude that the mean weight for non-top- 20 starters is
less than the known value for top-20 teams? Conduct hypothesis test using α=0.01.
2. A drug manufacturer claimed that the mean potency of one of its antibiotics was 0.800. A
random sample of n=100 capsules were tested and produced a sample mean of 0.797,
with a standard deviation of s= 0.008. Do the data present sufficient evidence to refute
the manufacturer’s claim? Let α = 0.05.
3. Suppose the average total cholesterol value for a random sample of 12 ISU students is 190
with a standard deviation (s) of 8. Also, the average total cholesterol value for a random
sample of 18 Purdue University students is 180 with a standard deviation (s) of 6. Do these
sample statistics provide sufficient evidence at α= 0.01 to claim that the average total
cholesterol value for the population of ISU students is statistically greater than the average
total cholesterol value for the population of Purdue university students? Hint: This
hypothesis test is for two means and one tailed. Here, you will use a pooled standard
4. A group of six, obese adult women had their weights recorded both before and 9 months
after having a diet treatment to help manage their weight. Observe the information presented
in the table below:
The weights of six obese adult women both before and 9-months after having a diet treatment
Before Diet Treatment After Diet Treatment
Test at α = 0.05 the hypothesis that for the group, there was a statistically significant average
decrease in weight from before diet treatment to 9 months after. Hint: This is hypothesis
testing for paired samples. Here, you will use a paired t test.