Question

7. In a certain city, a man recorded the speeds of cars driving past his

house, where the speed limit sign read 20 mph. The mean of 100 readings


was 22. 95 mph, with a standard deviation of 3. 68 mph. One car's z-score


was -1. 4. How fast was that car going? (Round to 2 decimal places) *


Your answer

Answer 1

We can use the formula for z-score to find the speed of the car:

z = (x - μ) / σ

where x is the speed of the car, μ is the mean speed of the cars, and σ is the standard deviation of the speeds.

Rearranging the formula, we get:

x = z * σ + μ

Substituting the given values, we get:

x = -1.4 * 3.68 + 22.95

x = 17.27

Therefore, the speed of the car was 17.27 mph.