Question about calculating a mean

I need to calculate the mean with the following data set. But for some reason I am completely blank. I know it's supposed to be easy, but when I tried solving it I got an answer that wasn't possible. Please help if you can, thank you.

Fifty college students selected from at random from the student directory were asked to respond to the question, “What is the ideal number of children for a family to have?” The responses were shown in the following table.

Ideal Number of Children........Frequency

0......................................4

1.................................... 9

2......................................25

3.................................... 8

4............ .........................3

5......................................1

I need to calculate sample mean Y, the standard deviation, the standard error, 95% confidence interval for the Mean of the population, and the probability for M to the estimated range of of a +-0.1 margin of error.

You don't need to do all of that for me because I have the formulas, but I know I just need the basic mean to be able to do all that and for some reason I can't solve for the mean. Can you help me out? And if possible, tell me how you did it? Thank you so much.

PS: I put this in basic probability and statistics because it seems that calculating a mean would be rather elementary, but if you think it would be better for me to put it in the advanced forum, please let me know.