Question

After accelerating for 20 seconds, a DeLorean sports car is a wide range of speeds that it can achieve, depending on traction. The distribution of speed follows in approximately normal distribution with the meaning of 80 mph and a standard deviation of 7.7 mph Marty wants the next acceleration run to be in the fastest 15% of all possible speeds how fast will the car have to go

Answer 1

Answer:

72mph

Explanation:

z = (x-μ)/σ, where x is the raw score, μ is the population mean, and σ is the population standard deviation.

z score for 15th percentile = -1.036

Mean = 80 mph

Standard deviation = 7.7mph

Hence,

-1.036 = x - 80/7.7

Cross Multiply

-1.036 × 7.7 = x - 80

- 7.9772 = x - 80

x = 80 - 7.9772

x = 72.0228mph

Approximately 72 mph