Question 1193773
500 exercised and 500 didn't, and the total is 1000
this is what you are given
----------C--------NC------Total
E------- 45-----------------500
NE------155---------------- 500
Total---200----------------1000


From that, you can fill out the rest of the table

----------C--------NC------Total
E------- 45-------455-------500
NE------155------345-------500
Total---200-------800------1000

a. 20%
b. 45/500 or 9%
c. 31%, assuming you can generalize the results to next year
d.If exercise and getting a cold are independent then the probability(E), 0.5, and probability(C), 0.2 equals the probability of P(E and C), which is 0.09. 
0.10 NE 0.09, so not independent. They are dependent to some extent.