On a standardized test, the mean is 37 and the standard deviation is 2.5. Approximately what percent of the scores fall in the range 32 - 42 ? A) 68%
B) 95%
C) 34%
D) 99%

B) 95%

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 37, standard deviation = 2.5

Approximately what percent of the scores fall in the range 32 - 42 ?

32 = 37 - 2*2.5

So 2 standard deviations below the mean

42 = 37 + 2*2.5

So 2 standard deviations above the mean.

This question is the percentage of scores within 2 standard deviations of the mean, so, by the Empirical Rule, it is 95%, option B.

19

step-by-step explanation:

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.