00:01
For this problem, we are basically doing a hypothesis test, where the null hypothesis is that the population mean, for the average time an employee stays with a company in their current positions, is equal to three years.
00:15
The alternative hypothesis is that the average time differs from three years.
00:20
It does not equal three.
00:22
We're told that we have a random sample of 50 employees, which yields a sample mean equal to 2 .79 years, where we are, told that the population standard deviation is 0 .76, and our level of significance, alpha, is equal to 0 .05.
00:47
So, to test this, i'll note that we're doing a two -tailed test at alpha equals 0 .05.
00:52
So we'll have two critical values, plus or minus the z score for a one -tail probability of 0 .025, which will then, in turn, be plus or minus 1 .96.
01:04
You can find that using a critical value table, i just have those values memorized.
01:08
So that means that we will reject the null hypothesis, concluding that the mean differs from three years, if our test statistic is greater than positive 1 .96 or less than negative 1 .96...