00:01
Let's take note what values are given here.
00:04
There are 15 measurements, so the sample size which is given as 15, and the x bar which is the sample mean given as 75, and the sample standard division 5, and the confidence level which is given as 99 percent, so we can write as 0 .99.
00:19
So we have to find the confidence interval for the population mean.
00:23
Remember the formula, the confidence interval for the population mean which is the sample mean plus or minus.
00:29
Because we know the sample standard division, so we have to use a t distribution.
00:34
So this is t alpha over 2, and times sample standard division divided by square root of the sample size.
00:40
Let's get the alpha value.
00:41
So the alpha is 1 minus confidence level, but we need alpha over 2, 1 minus 0 .99, and divide by 2 which would be 0 .005, and also we need the degrees of freedom, and minus 1 which is 15 minus 1 would be 14.
00:55
Let's get the t value here.
00:56
So i'm going to use the inverse t function...