Answer:
a total of 12
Step-by-step explanation:
1,2,3,4,5,6,10,12,15,20,30,60,
factors are Numbers we can multiply together to get another number.

It approximately the answer (17) if rounded
Answer:


And we are 95% confident that the true difference means are between 
Step-by-step explanation:
We know the following info:
sample mean for group 1
sample mean for group 2
sample standard deviation for group 1
sample standard deviation for group 2
sample size group 1
sample size group 2
We want to find a confidence interval for the difference of means and the correct formula to do this is:

Now we just need to find the critical value. The confidence level is 0.95 then the significance is
and
. The degrees of freedom are given by:

The critical value for this case would be :
And replacing into the confidence interval formula we got:


And we are 95% confident that the true difference means are between 