00:01
Hi, i'm david and i'm here to help you answer your question.
00:03
Now let me pick up the question here.
00:06
In this question we want to reveal about the normal distribution.
00:10
And here, let me remind you that it will have x followed by the normal with the mean of the standard deviation.
00:18
It will turn the x minus the mean of a standard deviation, we should get the standard normal.
00:24
Here we have the x, it will be the score of the test followed by the number.
00:32
Normal when the mean equal to the 74, standard division equal to 9.
00:38
And the question i want asking us to find the probability that the score of the student below 60, so x smaller than the 60.
00:51
To find this probability, we need to turn the x into the z.
00:55
To do that, we have to use the formula here.
00:58
We turn the 60, we minus the mean, divided by standard deviation.
01:05
If we do the calculation, we have z be smaller than 60 minus 74 divided by 9 equal to the minus 1 .5, 6.
01:18
Now to find this probability, i need to bring up the z table.
01:22
So let me copy the z table for you.
01:26
Let me put the table out on the side on the right here.
01:30
And then we see the z score would be the minus 1 .5 and 6.
01:37
So therefore the corresponding probability it will equal to the 0594...