00:01
So the formula for a z -score is the data element minus the mean divided by the standard deviation.
00:14
So they're asking me for the z -score for a value of 40, so that's going to be 40.
00:21
They tell me that the mean is 50 and the standard deviation is 4 .5.
00:29
So that's going to be negative 10 divided by 4 .5, and that is negative 2 .22, or the fourth answer choice.
00:50
Question 20 gives me some data.
00:54
29 the second to write it.
01:05
So the mean is the average.
01:08
So we're going to add all those up, so i get 353, and divide by the number of items.
01:24
One, two, three, four, five, six, seven, eight.
01:30
So 353 divided by 8 is 44 .125.
01:39
So that's the mean.
01:42
The median, i'm just going to count in and find the number that's in the middle.
01:48
So jumping in from both ends, so it's the number that's in the middle between those two, so that's going to be 49 is the median...