00:01
Hi, i'm david and i'm here to help you answer your question.
00:04
Now let me bring up your question is about the normal distribution.
00:09
Let me remind you that even the x that followed by the normal, the mean and the standard deviation, and if we tell the x we manage the mean of a standard deviation, we obtain the standard normal.
00:24
But if we take the sample mean x bar, we minus the mean of a standard deviation, we need to define x to square of n in order to obtain the standard normal.
00:34
In the question here, we are given the x that will follow by the normal, when the mean equal to the 195, standard division equal to the 8 .6.
00:50
Now in the question a, we need to find the probability that the distance x will be greater than 207 .5.
01:01
Now to find this probability i need to convert the x into the z to do it i need to apply the formula for one x only so i tend to what to 07 .5 we minus the mean 195 over the standard deviation 8 .6 and if we compute we will have the z will be greater than 207 .5 minus 195 divided by the 8 .6 equals to the 1 .45.
01:34
The next step to find this probability i need to bring up the z table.
01:39
Let me copy the z table and then put the table on the right here.
01:44
Notice that the table i bring here, it has the negative g score with the probability on the left tail.
01:49
Right now it's not compatible yet.
01:52
It will look at the graph here and let's say this value here will be the 1 .45.
02:00
Then the probability we're looking for equal to the area on the right.
02:05
But if we consider this value will be the minus 1 .45, then the area on the left equal to the area on the right...