00:01
All right, so for this problem, we have an annual cost of dogs, has an average of 100 in a standard deviation of 30.
00:11
We're told that cats have a standard deviation of cost, or a mean per cost of 120, with a standard deviation of 35.
00:19
And then it also tells us that the distribution of the difference between the two has a mean of negative 20.
00:31
By taking 20 minus 100, and a standard deviation of that difference is 46.
00:39
So we're told that the, so really we're doing everything based on this right here, and that's cats minus dogs, or dogs minus cats, right? taking the dogs minus the cats.
00:49
So we are wondering what is the probability that the dog costs higher than the cat.
00:58
So really we're looking what's the probability that x? bar is greater than zero, right? that the dog cost is greater than the cat cost.
01:10
So to compute this, we're going to compute a z value, which is going to be x minus mu over sigma...