Question

#5

Assume that the speed of automobiles on an expressway during rush hour ls nomaly distributed with a mean of 66 mph and a standard deviation of 6 mph What percent of cars are traveling slower than 58 mph? Click the icon to view page 1 of the title of 2-cores m Click the icon to view page 2 of the table of com The percentage of cars wing wwe than (Type an integer or a decimal rounded to two decimal places needed)

Answer 1

Solution:

Given that,
μ =66, σ=6
P(X< 58)= p{[(x- μ)/σ]<[(58- 66)/6]}
=P(z<-1.33)
=0.0918 ( From Standard Normal table)
= 9.18%

The percentage of cars traveling slower than 56mph is 9.18%

Answer 2

SOLUTION :

P(x < 58) 

= p(z < (58 - 66)/6) 

= P(z < - 1.3333) 

= 0.0912 = 9.12% (from cumulative ND table)

So, 

Percentage of cars travelling slower than 58 mph = 9.12% 9ANSWER)