More and more college students are choosing not to buy the meal plan on campus and instead buy or even make their own meals. A study at a local university revealed that in a random sample of 250 seniors last year, 49% of them no longer bought the meal plan, whereas this year, in a different random sample of 240 seniors, 62% of them no longer bought the meal plan.
What is the 95% confidence interval for the true difference in proportions of seniors between this year and last year who do not buy the meal plan anymore? (Round your answers to three decimal places.)
I figured out the point estimate to be: 0.13
And the standard error to be: 0.04451
and the margin of error with 95% confidence to be: 0.087
But having difficulty finding that interval.