SOLUTION: The length of time that it takes Ken to drive to work represents a normal distribution with a mean of 25 minutes and a standard deviation of 4.5 minutes.If Ken allows 35 minutes to

 

Hi

Population: mean is 25 and the deviation is 4.5.

P(x ≥  35) = 1 -  P(z ≤ 2.222) = 1 - .9869 = .0131 0r 1.31 % chance of being late



For the normal distribution: Below:  z = 0, z = ± 1, z= ±2 , z= ±3 are plotted.  

Area under the standard normal curve to the left of the particular z is P(z)

Note: z = 0 (x value: the mean) 50% of the area under the curve is to the left and 50%  to the right





one  standard deviation from the mean accounts for about 68% of the set 

two standard deviations from the mean account for about 95%

and three standard deviations from the mean account for about 99.7%.