the international tennis federation has specific requirements for the weight of tennis balls. of the hundreds of tennis balls produced by big fuzz per hour, seven are selected at random and the sample mean weight is measured (in grams). you have been provided with data for the last 100 hours. use the first 25 samples as the base period and draw an x and s2 chart with the data. what assumptions about the data are you required to make? does this process appear to be in control? comment.