On Professor Grindstone's final exam the mean score was 78 and the standard deviation 10. He wants to "curve" the exam so that the middle 50% of the...

6.On Professor Grindstone’s final exam the mean score was 78 and the standard deviation 10. He wants to “curve” the exam so that the middle 50% of the students get C’s. (a)Find a z score for which the area under the standard normal curve from –z to z is 50%.(b)Find the range of scores which will be assigned a grade of C.