Problema Solution
a radar unit is used to measure speeds of cars on a motorway. the speeds are normally distributed with a mean of 60 mph and a standard deviation of 10 mph. what is the probability that a car picked at random is travelling at 55 mph?
Answer provided by our tutors
Let x be the random variable that represents the speed of cars.
x has μ = 60 and σ = 10. We have to find the probability that x is 55 or P(x = 55)
For x = 55 , z = (55 - 60 / 10 = -0.5
P(x = 55) = P(z = -0.5) = 0.308538
The probability that a car selected at a random has a speed equal to 55 mph is equal to 0.308538.