00:01
Hi, i'm david and i'm hitchie, have you answered your question? now let me pick up your question here.
00:07
In the question here we are going to discuss about the normal distribution.
00:11
Let me remind you that if the x that followed by the normal, with the mean and the standard deviation, and if the x minus the mean of a standard deviation, we'll pretend the standard normal.
00:23
In the question here, we're given the lifetime of the tvx, we're followed by the normal, with the mean it will equal to the 60 months and the standard division equal to the four months.
00:37
And now the company wants to have the tv with the 95 % chance of being problem free during the guarantee period.
00:48
So that doesn't mean that the chance that the tv has a problem will be only 5 % chance.
00:54
So x smaller than equal to some value a and this will be equal to the 5 % and to find the volume the a, i need to convert the x into the z.
01:06
To do it, i need to apply the formula here.
01:09
So i get a minus the mean by the standard deviation, and then equal to the 5 % will be the 0105.
01:21
Now the next time we need to turn the zubon 05 into the formula probability...