Stats questions. Out of 3000 students in a School of Public Health, 1500 students defined themselves regular dietary supplement users...?

I'm completely stuck, can anyone help?

1) Out of 3000 students in a School of Public Health, 1500 students defined themselves regular dietary supplement users. If you take a sample of 20 of them, what’s the standard error of the proportion (p) of those who defined themselves as dietary supplement users in the school?

(Give your answer to at least 3 decimal places)

2) Imagine the correlation between high school GPA and college GPA in a population was 0.37. Imagine we randomly select 200 people and obtained the correlation of 0.34. What’s the standard error of Z’ for N=200?

3) On a measure with a mean of 10 and a standard deviaton of 2, Sumathi scored 13. What proportion of people score farther from the mean than Sumathi?

(Give your answer to at least 3 places past the decimal point)