Mopeds (small motorcycles with an engine capacity below 50 cm3) are very popular in Europe because of their mobility, ease of operation, and low cost. Suppose the maximum speed of a moped is normally distributed with mean value 46.8 km/h and standard deviation 1.75 km/h. Consider randomly selecting a single such moped. (a) What is the probability that maximum speed is at most 49 km/h

Respuesta :

Answer:

The probability that the maximum speed is at most 49 km/h is 0.8340.

Step-by-step explanation:

Let the random variable X be defined as the maximum speed of a moped.

The random variable X is Normally distributed with mean, μ = 46.8 km/h and standard deviation, σ = 1.75 km/h.

To compute the probability of a Normally distributed random variable we first need to convert the raw score of the random variable to a standardized or z-score.

The formula to convert X into z-score is:

[tex]z=\frac{X-\mu}{\sigma}[/tex]

Compute the probability that the maximum speed is at most 49 km/h as follows:

Apply continuity correction:

P (X ≤ 49) = P (X < 49 - 0.50)

                = P (X < 48.50)

                [tex]=P(\frac{X-\mu}{\sigma}<\frac{48.50-46.80}{1.75})\\=P(Z<0.97)\\=0.83398\\\approx 0.8340[/tex]

*Use a z-table for the probability.

Thus, the probability that the maximum speed is at most 49 km/h is 0.8340.