At an intersection, the red light times are normally distributed with a mean time of 3 minutes and a standard deviation of 0.25 minutes. approximately what percent of red lights last between 2.5 and 3.5 minutes?

P = 95%

Step-by-step explanation:

The average is:

The standard deviation is:

.

We want the probability that the red light lasts between 2.5 minutes and 3.5 minutes

This is:

Now we must transform these values to those of a standard normal distribution to facilitate calculation by using the probability tables.

This is:

---------- (By the symmetry of the standard normal distribution)

When you search for the normal standard table, you get the following value:

The answer is 95% from calculation

Step-by-step explanation: