Real-Life Math -- Solution
You want to figure out how the results of your study compare with the statistical norm.
60 men, half of whom are fit and half of whom are not
Fit -- 30
Unfit -- 30
Statistically, 14 of every 25 men in this age group will die by age 75. What percentage is that?
14 / 25 x 100 = 56 percent
What would that mean for your group?
Fit
30 men x 0.56 = 16.8 or 17
Unfit
30 men x 0.56 = 16.8 or 17
17 + 17 = 34
You would expect 34 of your 60 men to die. You have an equal number of fit and unfit men, so if fitness is not a factor, you would expect the deaths to be evenly distributed between the two groups. But your numbers tell you something different.
By age 75
Fit -- 13 dead, 17 alive
Unfit -- 22 dead, 8 alive
Fit
13 dead / 30 total x 100 = 43 percent
Unfit
22 dead / 30 total x 100 = 73 percent
From your study, it would seem that men who are fit have a much better chance of surviving to age 75 than men who are not fit.