Question

7) Let the random variable X represent the amount of money Dan makes doing lawn care in a randomly selected week in the summerAssume that is Normal with mean $ 240 and standard deviation $60. the probability that in a randomly selected week, Dan will make less than $255 is :
A. 0.6
B. 0.7
C. 0.8
D.0.9
E. 1

Answer 1

Answer:

Option A. 0.6 is the right answer.

Step-by-step explanation:

Given information is:

Mean = $240

SD = $60

The probability of Dan making less than $255 has to be found.

Let x = 255

First of all, we will find the z-score of the given value

$z = \frac{x-mean}{SD}\\z = \frac{255-240}{60}\\z = \frac{15}{60}\\z = 0.25$

Now the z-score table will be used to see the probability of less than 0.25

Using the z-score table, we get:

P(x<0.25) = 0.5987

As the answer choices are rounded off to one decimal place, we will round off our answer to one digit after the decimal point

0.5987 => 0.6

Hence,

Option A. 0.6 is the right answer.