Problem 10-28 The following is a control chart for the average number of minor errors in 22 service.

Problem 10-28 The following is a control chart for the average number of minor errors in 22 service reports.

a. Calculate the observed mean, expected mean, standard deviation and z value for the median and up/down test. (Negative amounts should be indicated by a minus sign. Round your answers to 2 decimal places.) Test        Observed        Expected        Std. dev          z Median   Up/Down

I know some of these answers are incorrect. Please assist