Scores on a test are normally distributed with a mean of 63.2 and a standard deviation of 11.7. Find Upper P 81, which separates the bottom 81% from the top 19%. Round to two decimal places.

(Upper P81) = 72.68

Step-by-step explanation:

Use the z-score formula:  

        x - mean

z =          Our goal:  find the x-value for the given inputs

           s. d.

Here we know s. d. (11.7) and mean (63.2)

Upper P81 is the upper boundary line of the area to the left of the left half  area 0.81:

          (Upper P81) - 63.2

0.81 =

                    11.7

Our job is to solve for (Upper P81).  Do this by multiplying both sides of this equation by 11.7, obtaining:

9.477 = (Upper P81) - 63.2, or

63.2 + 9.477 = (Upper P81), or, finally,

(Upper P81) = 72.68

the difference between a number and 5 is -2.

step-by-step explanation:

notice that the equation you are given has -2 (negative 2) on the right side, not 2. when you subtract 5 from a number n, you are finding the difference between the number and 5.

the difference between a number and 5 is -2.

exa:

)

3+11

14

step-by-step explanation:

from this example, we can see that subtracting with integers is the same as adding the opposite. we can solve using a number line or by using the saying "keep, change, change" to us solve. it is important to remember that we can subtract a negative and end up with a larger number than we started with.