posted by sarah .
refer to the schools data set in appendix m which refers to the 94 school districts in northwest Ohio. divide the school districts into two groups. include all schools with less than 2000 students in one group and the other being the ones with more than 2000. Compute the mean teacher salary for the two groups. At the .05 significance level, can we conclude that the mean teacher salary is higher in the larger school districts?
B. Compute the mean amount spent per pupil for the large and the small districts. At the .05 significance level, can we conclude that there is a difference in the mean amount spent/
C. compute the mean daily percent of students attending for the large and small districts. At the .05 significance level, can we conclude that there is a difference in the mean daily attendance
We do not have the data to do the computations. However, this might help.
Find the mean first = sum of scores/number of scores
Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.
Standard deviation = square root of variance
Z = (mean1 - mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√(n-1)
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to that Z score.