Answer: 0.5263
Explanation:
Given : The completion times for a job task range from 11.8 minutes to 19.4 minutes .
The density function for uniform distribution function for interval [a,b] :-

Then the density function for the given situation:-

The required interval :

Now, the probability that it will require between 12.8 and 16.8 minutes to perform the task will be :-
