00:01
In this question, we have a paragraph of information.
00:03
Let's start by writing it in probability notation.
00:06
Nearly 20 % of bachelors in 2019 were business degrees.
00:11
So probability of business degree is 20%.
00:15
If you pick a bachelor at random, probability is a business degree, 20%.
00:20
27 % of students at this university study business.
00:25
Okay.
00:27
So i don't think we actually need this.
00:29
We can ignore that.
00:29
Just go on to the next bit.
00:31
Probability of business at this university is 27%.
00:35
Probability of living on, of commuting, okay, so commute, i'll just put c for commute, is 41%.
00:47
The probability of being a business student or living on campus is .617.
00:55
Okay, part a, what is the probability of living on campus? so i'm going to draw a then diagram here.
01:04
Everybody is either a business student or not.
01:08
Everybody either lives on campus or does not.
01:12
Now, if i label these, a b, c and d.
01:17
A is people who are business students, but commute.
01:20
B, people who live on campus and are business students.
01:24
C live on campus, but they're not business students.
01:26
D neither.
01:28
Now, i know that a plus b.
01:32
Makes up 0 .617.
01:35
That's everyone who meets at least one of the criteria.
01:37
I know that a plus d is everyone who doesn't live on campus, 0 .41.
01:44
So b plus c must be the other 0 .59.
01:48
Because if you add up all four places here, you cover the entire sample space, they all add up together to 100%.
01:56
Now from here, i can get a.
02:00
A is 0 .617 minus 0 .59...