Show transcribed image text Homework 2 (note: do not use the function in the calculator, and give the results. The necessary steps need be shown): How large a sample ?s required if we want to have 95% confidence that the average hardness of a sample of shafts is within 0.3 (margin of error) of the expected value if the variance is known to be 1.0, 2.0, 3.0, 4.0, 5.0, 6.0? Using the Excel spreadsheet to plot the relationship between the sample size (Y-axis) vs. standard deviation (sigma). If the observed concentration readings are 1.27, 133, 1.19, and 1.24, determine 95% confidence for the mean concentration assuming variance = 0.003.