15. if gallup had used a random sample of 1,500, what would happen to the margin of error? explain your answer.

The margin of error would decrease

Step-by-step explanation:

Assuming the sample size Gallup used previously is less than 1500

Margin of error = t×sd/√n

From the formula above, the margin of error varies inversely as the square root of sample size

The smaller the sample size the larger is the margin of error and the larger the sample size the smaller is the margin error

Since the sample size increased the margin of error would decrease

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: