Statistics help please?

[amdt57]

An important issue facing Americans is the large number of medical malpractice lawsuits and the
expenses that they generate. In a study of 1228 randomly selected medical malpractice lawsuits, it was
found that 856 of them were later dropped or dismissed. Construct a 99% confidence interval estimate of
the proportion of medical malpractice lawsuits that are dropped or dismissed. Round the confidence
interval limits to three significant digits.


i need to know how to do it not just the answer

[tate8]

n = 1228
x = 856
p' = 856 / 1228 = 0.697
? = 0.01, then z = 2.576

99 % confidence limits:

0.697 ± 2.576 * ?[0.697 * (1-0.697) / 1228] = 0.697 ± 0.03378 = (0.663 to 0.731)
Dropped or dismissed medical malpractice lawsuits make 66.3 to 73.1 %