Suppose a new treatment for a certain disease is given to a sample of n=200 patients. The treatment was successful for 166 of the patients. Assume these patients are representative of the population of individuals who have this disease. (a) Calculate the sample proportion of patients who were successfully treated. (b) Calculate the 95% confidence interval for the population proportion of patients who are successfully treated. (c) Write a sentence that correctly interprets this interval. (3.0 points)

Answer 1

The following is a hint for you to get started.

Use a confidence interval formula for proportions:

CI95 = p ± (1.96)(√pq/n)
...where p = x/n, q = 1 - p, and n = sample size.

Using your data:
p = 166/200
q = 1 - p
n = 200

Convert fractions to decimals. Calculate using the formula above.

I'll let you take it from here.

Answer 2

CI95= 0.855 or 0.805
Why 1.96 in the formulae ?