Afire department in a rural county reports that its response time to fires is approximately normally distributed with a mean of 22 minutes and a standard deviation of 11.9 minutes. approximately what proportion of their response times is over 30 minutes?

Answer-

In 25.15% cases their response times is over 30 minutes.

Solution-

Hint- Calculating the z-score (how much standard deviations away from the mean) and then getting the corresponding probability value from normal distribution table we can get solution.

Applying the formula for Z-score,

Here,

X = score = 30,

μ = mean = 22,

σ = standard deviation = 11.9

Putting the values,

(Subtracted from 1 as the values of area to the left of the Z score is given in table, but we need the area right to Z score as response times more than 30 minutes is asked)

answer: on graphs, the open and closed circles, or vertical asymptotes drawn as dashed lines us identify discontinuities.

as before, graphs and tables allow us to estimate at best.

when working with formulas, getting zero in the denominator indicates a point of discontinuity.

when working with piecewise-defined functions, check for discontinuities at the transition points where one piece ends and the next begins.

step-by-step explanation:

the answer is a.

135 and 80

step-by-step explanation: