Confidence Interval Help

#1
I am really stumped on this one:

In a sample of 400 seeds, 240 germinated.

Estimate the true germination rate with a 90% and 99% confidence intervals.

Spent hours trying to figure this out. Can anyone help me out?
 
#2
Germination rate

Here's a thought.

Treat the germination rate as a proportion. The proportion of seeds that germinated would be 240/400 or 0.6.

Since the sample size is relatively large, you can assume that the sample proportion is approximately normally distributed. Using this assumption, you can compute a confidence interval for the true germination rate.

The way to do this is explained at http://stattrek.com/Lesson4/Proportion.aspx . This web page even works out a sample problem that is very similar to the problem you face. Just follow the steps shown in the sample problem, and you can compute a confidence interval for the true germination rate.

Good luck.