Answer to Question #329417 in Statistics and Probability for Betty

Question

In an obstetric hospital 17.8% of 320 women were delivered by forceps in 1980. What is the standard error of this percentage? In another hospital in the same region 22% of 185 women were delivered by forceps.

(a) What is the standard error of the difference between the percentage at this hospital and the first one? ( 8 marks)

(b) What is the 95% confidence interval of the differences between those two percentages?

(4 marks)

(c) Was the difference in proportions statistically significant? ( 3 marks)