Posted by Winona on .
solve: our health organization is interested in estimating the average value of outstanding accounts receivable. After selecting a sample of 100 accounts, suppose that the mean was $120 and the standard deviation was $40. Use these data to construct a 98% confidence interval. how do i solve?

statistics 
PsyDAG,
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (.01 for twotailed) and its Z score (score in terms of standard deviations).
98% = mean ± 2.33 SEm
SEm = SD/√n