Hi! I am having a hard time with my statistics homework. Specifically, with finding the standard deviation. Here is one example:

According to a recent study, 28% of American college students graduate with no student loan debt. Suppose we obtain a random sample of 136 American college students and record whether or not they have student loan debt.

1)What is the mean of the distribution of^p?

• I know this is 0.28 (it was correct)

2) What is the standard deviation of the distribution of^p?

• I cannot get this part right

Here is another example:

According to a recent study, 78% of American children (age 2 - 9) believe in Santa Claus. Suppose we obtain a random sample of 139 children in this age group and ask them whether or not they believe in Santa Claus. Answer the following(Round your answers to four decimal places when appropriate):

1) Can the sampling distribution of^pbe approximated by the normal distribution?

• Yes (Correct)

2)What is the mean of the distribution of^p?

• 0.78 Correct

3) What is the standard deviation of the distribution of^p?

• I cannot get this correct. After getting it 0 points on the problem, the right answer showed up. It was "0.035135912882701". I don't know how they got this answer.

Thank you