The time between work-related injuries at the Imperial Tool and Die Co. during a given span of time resulted in the following 20 observations, where time was measured in weeks:

\((9.68,6.97,7.08, .50,6.71,1.13,2.20,9.98,4.63,7.59,3.99,3.26\), \(.92,3.07,17.96,4.69,1.80,8.73,18.13,4.02)\).

(a) Define and graph the empirical distribution function.

(b) What is the estimated probability that there will be at least 8 weeks between work-related injuries?

(c) What is the probability that there will be between 4 and 8 weeks between work-related injuries?

(d) Acting as if the EDF is the true CDF of time between work-related injuries, calculate the expected value of time between injuries. Is the value you calculated equal to the sample mean? Why or why not?