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
Answer:
It's close between Y and Z, but I'd go with Z
Step-by-step explanation:
≈-2.2360679775
An expression of that statement would look like:
n + 7 • 3
Here are the combinations:
1x18 = 18
18x1 = 18
9x2 = 18
2x9 = 18
6x3 = 18
3x6 = 18
The denominator can be 3 if the numerator is 1