The average age for licensed drivers in a county is 426 12

The average age for licensed drivers in a county is = 42.6, = 12, and the distribution is approximately normal. A county police officer was interested in whether the average age of drivers receiving speeding tickets differed from the average age of the driving population. She obtained a sample of N = 16 drivers with speeding tickets. The average age for this sample was M= 33.6.

Solution

normal distribution formula:

here x=N*M=16*33.6=537.6

      and = 42.6, = 12,

                                        z=(537.6-42.6)/12

                                          =495/12 =41.25

        it chang as above way