Scores of an IQ test have a bell-shaped distribution with a mean of 100100 and a standard deviation of 1414. Use the empirical rule to determine the following. (a) What percentage of people has an IQ score between 7272 and 128128?

95% of people have an IQ score between 72 and 128.

Step-by-step explanation:

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

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

95% of the measures are within 2 standard deviation of the mean.

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

In this problem, we have that:

Mean = 100

Standard deviation = 14.

(a) What percentage of people has an IQ score between 72 and 128?

72 = 100 - 2*14

So 72 is two standard deviations below the mean.

128 = 100 + 2*14

So 128 is two standard deviations above the mean.

By the Empirical Rule, 95% of people have an IQ score between 72 and 128.

the third picture

step-by-step explanation:

u = -(6/7)w

step-by-step explanation:

place all values with 'u' on one side of the equation.

4u + 8w = - 3u + 2w

4u + 3u = 2w - 8w

further simplify the equation by solving the addition and subtraction.

7u = - 6w

make 'u' the independent variable by placing its co-efficient on the right-hand side.

u = - (6/7)w