<PRE><B>Question 856507</B>
if i got the counts right, these are the numbers;


&lt;pre&gt;
                               female      male     total

students                         120        130       250
black                             20         20        40
white                            100        110       210


greater than 80%                  65         40        105
black                             10         15         25
white                             55         25         80


less than or equal to 80%         55         90        145
black                             10          5         15
white                             45         85        130


&lt;/pre&gt;


answers to the questions:


i) Given a person was a male from the minority group, what is the probability he had an average over 80%?


20 males from a minoty group and 15 of them have 80% or higher so the probability is 15/20 = 3/4 = 75%
 

ii) What is the probability that a person selected at random was male, did not come from the minority group, and had an average less than 80%? 


this would be a white male with an average less than 80%.
from the table, there are 85 of them.
the probability is therefore 85/250 = 34%




</PRE>