00:01
So considering that we have a normal distribution for x with mean 100 and standard deviation 10, we can find the probability in item a that x is greater than 95, considering the z score method.
00:17
So basically this means that we are going to compute this in the stand norm distribution by computing the z score for the value 95.
00:26
So this is the formula that we use to compute the z score, which basically means that this he is graded in minus 1.
00:34
So, yeah, so we have 95, just like checking here the calculations.
00:46
So basically here is actually minus 0 .5.
00:53
But now we can use the normal table to find this standard normal table to find this answer, which is 0 .6915.
01:02
Now for letter b, we should find here what is the probability that x is less than 75, which is the same as using the z score.
01:14
75 minus 100 divided by 10.
01:19
And in this case, this will be equals to the probability of set being greater than 2 .5.
01:27
And using the normal table, this is 0 .0062.
01:35
Now for letter c we should find here two probabilities.
01:39
The probability that x is smaller than 70 and the probability of x being greater than 1 to 5...