Use the following to answer Question 910The Lightning Bolt E

Use the following to answer Question 9-10.The Lightning Bolt Electric Car company claims their new car \'\'The Buzzer\'\' can travel on average 170 miles on one charge (mu = 170 miles). It s known that the population distribution associated with the distance per charge in normally distributed with standard deviation of 30 miles. 9. Approximately, what is the percentage of cars that travelled between 170 and 260 miles on average? 10. Approximately, the middle 95% of the cars fall between which two values?

Solution

9)

Mean=170

SD=30

260= mean*3 SD= 170+3*30= 260

We know that 99.7 % of the measurement in normal population lie with in the range of

Since the distribution is symmetry, 99.7/2 =49.85 % falls within mean and mean+3*sd

The correct answer   C   49.85%

10).

Mean -2*sd = 170 -2*30=110

Mean +2*sd = 170+2*30=230

Approximately 95% of the measurement in normal population lie with in the range of

Answer A    110 miles and 230 miles