00:01
This problem says a population of values has a normal distribution with a mean of 107 .6 and a standard deviation of 63 .4.
00:07
A random sample of size n equals 129 is drawn, but first for a we want to find the probability that a single randomly selected value is between 90 .9 and 116.
00:17
And to figure that out, since we were told this population is normal, we can use normal cdf in our calculator.
00:23
And with normal cdf, the first two things you need are the lower and upper bounds you want the probability between.
00:28
In our case, we want to be between 90 .9 and 116.
00:32
And that's followed by the mean and the standard deviation of your population, which would be 107 .6.
00:38
And the standard deviation is 63 .4 given.
00:41
And we were told to round to four decimal places, so this probability comes out to 0 .1566.
00:49
And for our next question, this time we're focused on our sample size of 129, and we want to know the probability that the sample mean is between 90 .9 and 116...