I have been banging my head against the table on this one for a week...
I have the first part, but I am looking for the answer to the second (bolded) statement:
Calculate the Z-Score to determine the percentage in specification and the percentage expected to be out of specs.
Formula: z = x - mean divided by standard deviation
Z = .025974 The chance probability is .489639
Calculate the average student score necessary for the district to retain funding. (Assume the standard deviation will not change)
Information provided.
Total Students:1000 (N = 1000)
Mean = 69.7 (u = 69.7)
Standard Deviation = 11.56
Last year, only 49% of the students scored 70% or >