00:01
Hi, i'm david and i'm here to have janssen your question.
00:03
In the question here, we are going to discuss about the central limit theorem.
00:09
Let me remind you that if the n greater equal to the 30, then the symbol mean x -pile will be approximately to the normal.
00:17
In such a way that if we take the x -bile, we manage the mean divided by standard division overscority of the n, we obtain the standard normal.
00:26
In this question here, we're given the mean equal to the 2.
00:30
Here we have the 2000, 2 .715 and we have given the sigma it will equal to the 0 .05, the n equal to the 35.
00:47
The question asks you find the probability that the sum will be between the 2 .693 and the 2 .725.
01:00
To find this probability, i need to convert the x -par into the z.
01:04
To do it, i need to apply this formula here.
01:08
And then on the left, i will have the 2 .693 and minus the mean, will be the 2 .7 -15, divided by the standard deviation, over square, the end will be the 35.
01:20
Same thing on the right, 2 .7 -25, and then minus the mean will be 2 .715 over the 0 .05, the bandwidth square root of the 35.
01:33
And every compute who have the z will be between 2 .693 minus 2 .715 divided by 0 .05 times squared into the 35 equal to the minus 2 .6 0.
01:50
And on the right 2 .725 minus 2 .715 divided by 0 .05 times square root of the 35 equal to the 1 .18.
02:07
Now to find this probability i need to bring up the z table.
02:11
Let me copy the z table and i will put the table on the right here.
02:20
Let me make it bigger.
02:23
Notice that the table i bring here, it has the negative score with the probability in the left tail...