00:01
So for this problem, the first thing that we want to do after looking at our table here is add in a column and row for the total across the rows and columns.
00:10
So we can see the total across the podunk column is 39.
00:14
The total across the upstate row is 48.
00:17
The total across the flights on time column should be 76.
00:23
And the total across the number late column should be 11.
00:26
So we have a grand total of 87 flights in our data set overall.
00:34
Now, having that, looking at the different probabilities that were asked to find, we're looking for, generally speaking, we can say that the probability of b given a is going to be equal to the number of things in the intersection of a and b, divided by the number of things in b.
00:53
So we can apply that formula for each one of the things that we're asked about.
00:58
So first we're looking at probability of on time.
01:04
So basically we can think of that as being on time given that it was a flight.
01:09
That would be 76 over 87...