The mean time to complete a task is 727 millisecond for 3rd graders and 532 milliseconds for 5th graders. The variances of the two grades are 12,000 for 3rd graders and 10,000 for 5th graders. The...

The mean time to complete a task is 727 millisecond for 3rd graders and 532 milliseconds for 5th graders. The variances of the two grades are 12,000 for 3rd graders and 10,000 for 5th graders. The times for both grades are normally distributed. You randomly sample 12 3rd graders and 14 5th graders. What is the probability that the mean time of the 3rd graders will exceed the mean time of the 5th graders by 150 msec or more?