00:01
Hi, i'm david and i'm here to help you and send your question.
00:03
Now let me bring up your question here.
00:05
In the question here we are going to discuss about the normal distribution.
00:10
Let me remind to you that if the x that follows by the normal, when the mean and the standard division, if we turn the x minus the mean of a standard deviation, we obtain the standard normal.
00:21
In this question here we have the score x will follow by the normal when the mean equal to the 36 standard division equal to the 4.
00:29
In the first question 1, want to find the percentage of the score x would be greater than the 30.
00:35
To find this probability, i need to convert the x into the z.
00:39
To do it, i need to apply this formula here.
00:42
And then i'll take the 30 and minus the mean will be the 36 over the standard deviation.
00:48
And if we compute, we have the z will be greater than it will be the minus 6 divided before.
00:53
It will equal to the minus 1 .50.
00:56
Now just in the z table we have this value it will be equal to can equal to the 0 .9 3, 3, 2 and in the percentage equal to the 93 % and that will be the answer for the first question 1.
01:29
Now for the question 2, once you find the percentage that the x will be between the 33 to the 35.
01:38
Again, i convert the x into the z.
01:41
It will be between the 33 minus the mean will be the 36 over the 4.
01:49
35 minus the 36 over the 4.
01:52
And then we get equal to the probability of the z will be between.
01:56
Here we have the 3 divided minus 0 .75.
02:03
And this will be minus 0 .25...