Class B insulation. Use the data in Table 3.1, but fit Weibull distributions.
(a) Plot samples from each temperature on the same Weibull probability paper.
(b) Use natural logs of the data and calculate the BLUEs of the corresponding extreme value parameters λ and δ for a temperature.
(c) Calculate the estimate of the 50th Weibull percentile for that temperature
(d) Use the chi-square approximation to get approximate 95% confidence limits for the Weibull shape parameter at that temperature
(e) Calculate a pooled estimate of the shape parameter using the BLUEs from the four temperatures.
(f) Use the chi-square approximation to get approximate 95% confidence limits for the common shape parameter. Is the failure rate significantly increasing or decreasing?
(g) From the Weibull plot, assess whether the true Weibull shape parameter has the same value at all temperatures.
