00:01
So your first question is dealing with finding out what the z value is, and i believe this is what your picture is supposed to look like, that you have the standard normal distribution with zero being in the center, and you have a z value that is to the left, and the area to the right of that is 0 .7611.
00:19
And so you can look up in your table of areas if you want, 0 .767676.
00:32
And find out that that corresponds to a z value of .71 and sorry when i write while i'm recording it does not identify my stylist very well in any case but we know that this z value is negative and you can also subtract and find the complement down here so that you can look it up directly but the z value is negative .71 now i'm on the next problem, you have a normal distribution with this mean and this standard deviation.
01:08
And you want to find the likelihood and you're told it's normal.
01:11
And so you want to find what the likelihood is of having a jump or distance that is 215.
01:18
So we need to convert that to a z value.
01:21
So we take this score minus the mean divided by the standard deviation and that gives us a z score rounded off to two decimals of 1 .2.
01:30
Now, once again, you can look up in your table 1 .2, but it's actually easier to look up symmetrically the area below negative 1 .2 because that will be the same is the area above positive 1 .2 and get that answer directly without subtracting.
01:49
So if you just look at a picture, it makes the symmetry easier.
01:52
Now, they tell us now that we're getting a measurement of 15 people in finding a mean, and we want to know what's the likelihood.
02:00
That the mean is higher than 204...