00:01
Here we have a normal distribution with a mean of 500 and a standard deviation of 10 .5.
00:06
So a, it says find the probability that they had less than 490.
00:12
This is going to be normal cdf from a score of zero to 490.
00:18
So there's my lower bound, my upper bound, my mean is 500, and then my standard deviation is 10 .5.
00:27
So go to your normal cdf calculator.
00:32
0 to 490 is the bounds we're adding up.
00:35
500 is our mean, 10 .5, and that gives me 0 .170452.
00:46
Part b, so i found the probability that they took the test, and their score was between 499 and 514.
00:59
So those are my lower and upper bound there...