00:01
So we're going to be doing a two sample t test with pooling since we're supposed to have the variance of the slow music paying how much people have for bar bills is the same as for fast music.
00:13
And we're assuming that the two mean amount spent would be equal and alternately that the slow music is causing a higher purchasing.
00:23
And the degrees of freedom will be that some of the two sample sizes, less two or 20, and our test statistic, well, we know that our, we'll have the 30 .53, less the 21 .63, and then we'll be dividing that by, and we do need that pooled p, or that pooled standard deviation.
00:51
And the standard deviation of the first group was 15 .7.
00:58
The second group was 9 .2 or $9 .20.
01:02
And then the that pooled variance is equal to the one less than the first sample size.
01:09
So we have 17 and the other sample size is 11.
01:12
And we take that 15 .7 squared plus the 9 .2 squared here.
01:19
And then we divide that by the degrees of freedom.
01:22
And the pooled standard deviation numerically comes out to be 13 .524...