It was reported by the National Forensic Center in the Guide to Experts Fees, 1998-99 that the average fee of forensic accountants for court testimony was 1500. Assume that the population standard deviation is 600. What is the probability that, in a random sample of 100 forensic accountants, the average fee falls between 1450 and 1600 per day?

Question

It was reported by the National Forensic Center in the Guide to Experts Fees, 1998-99 that the average fee of forensic accountants for court testimony was 1500.  Assume that the population standard deviation is 600.  What is the probability that, in a random sample of 100 forensic accountants, the average fee falls between 1450 and 1600 per day?

PsyDAG · Answer

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 proportions related to your Z scores.