00:01
So you're given two samples, and your first sample has a mean of 45, a standard deviation of four, and a sample size of seven.
00:10
And your second sample has a mean of 35, a sample standard deviation of six, and a sample size of 12.
00:20
And so i believe your test is supposed to be a one -tail test, so you're assuming that the two means are equal.
00:30
And alternately that the first mean is larger than the second mean.
00:35
And on your first question, you asked to find the pool, because we're going to be assuming that the variances are equal, and we want to find out what that pool variance is.
00:46
And so that value will be to take the one less than the sample size times the square of the variance of the first sample variance, which is 16, and then one less.
00:59
And the sample size times the variance of the second, which is 36.
01:04
And then we add the two sample sizes and subtract away two.
01:09
And this will give us our value in just one quick second.
01:15
Let me do that calculation for you.
01:20
So i have left parentheses 6 times 16, which i think is 96 plus 11 times 36.
01:27
And then we're dividing that by, let's see, that is.
01:30
That is 17, dividing by 17.
01:34
Excuse me.
01:35
And so that variance is 28 .9412.
01:42
That's our variance.
01:44
And then question two asked for a test, a t test, what number of degrees of freedom do you use? and we use this.
01:56
We use the 7 plus the 12 less 2.
01:59
So we have 17 degrees of freedom.
02:03
And we're asked to use in part three to use an alpha level...