The timber-beam data of Prob. 1.1 is to be used to make probability statements about strength and deflection.
(a) Based on the histograms and professional judgment, select two possible models for each set of data. Check for fit with plots on probability paper and comparative χ2 statistic likelihoods.
(b) Assuming that normal distributions provide satisfactory fits, state 90 percent confidence limits on the means and standard deviations.
Prob. 1.1
Use a table of random numbers to take five independent samples, each of size 10 observations, of a random variable uniformly distributed on the interval 0 to 100. From each of the five samples estimate the mean and standard deviation of the distribution. All the estimates produced by the class will be plotted in a histogram and their mean and standard deviation will be estimated. What are the true values of these moments of the estimator of the mean?