thing about the value of the population mean reading grade level for apps available for purchase that are targ toward young people The following table is similar to the table that appears in Example 12 4 The What You Know information has been provided Complete the table by filling in the How You Know It column What You Know The sampling distribution of x is centered at the actual but unknown value of the population mean An estimate of the standard deviation of x which describes how the x values spread out around the population mean is 0 31 Of x H l f 0 L J S H 0 X 0 ox X H H z X S Vn 0 fl X 34 V1 8 1 8 33 33 1 8 1 8 34 33 1 8 How You Know It