A survey asks a random sample of 1500 adults in Ohio if they support an increase in the state sales tax from 6% to 7%, with the additional revenue going to education. Let X denote the number in the sample that say they support the increase. Suppose that 40% of all adults in Ohio support the increase.

a. The mean of X is:
b. The standard deviation of X is?

a) 600

b) 18.97

Step-by-step explanation:

For each adult, there are only two possible outcomes. Either they support the increase, or they do not. The probability of an adult supporting the increase is independent of other adults. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

The expected value of the binomial distribution is:

The standard deviation of the binomial distribution is:

Sample of 1500 adults

So

Suppose that 40% of all adults in Ohio support the increase.

This means that

a. The mean of X is:

b.The standard deviation of X is?

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18

one set of data has more variation than the other. hope this !