Q.4. Compressive strength test results done on 39 concrete specimens, which are known to be normally distributed, are given in the table below in ascending order. (a) Plot the given data on the "normal probability paper" by calculating the cumulative frequency values using the Weibull plotting position fornula. Draw the straight line best fitting to the data points. (b) Calculate the mean and the standard deviation values of the data analytically and also show on the plor. Compare. (c) Calculate the probability OF result being less than equal (28 + 0.1 (a + b + d + g + h + ) MPa, using the plot and the Standard Normal Cumularive Probability Table. Compare. (d) Calculate the limits of the confidence intervals for the mean and the standard deviation of the strength at the P = 95% confidence level using exact distributions. Or to 272 3 7 9 10 13 x (mPa) 26.98 26.99 27.10 27.37 27.85 27.97 28.28 28.65 28.82 28.89 28.99 29.03 29.04 14 15 16 17 IN 19 20 21 23 24 25 x (mPa) 29.04 29.34 29.57 29.64 29.67 29.73 29.81 30.03 30.38 30.38 30.57 30.97 31.12 272 29 30 31 32 23 3.4 35 36 37 38 39 x (mPa) 31.19 31.23 31.44 32.02 32.07_32.20 32.20 32:21 32.70 32.84 32.97 33.19 33.51​