Question

A survey of 2315 adults in a certain large country aged 18 and older conducted by a reputable polling organization found that 416 have donated blood in the past two years. Complete parts (a)and (b) below. Click here to view the standard normal distribution table (page 1). LOADING... Click here to view the standard normal distribution table (page 2). LOADING... (a) Obtain a point estimate for the population proportion of adults in the country aged 18 and older who have donated blood in the past two years. ModifyingAbove p with caretequals nothing (Round to three decimal places as needed.) (b) Construct and interpret a 90 % confidence interval for the population proportion of adults in the country who have donated blood in the past two years. Select the correct choice below and fill in any answer boxes within your choice. (Type integers or decimals rounded to three decimal places as needed. Use ascending order.) A. We are nothing % confident the proportion of adults in the country aged 18 and older who have donated blood in the past two years is between nothing and nothing. B. There is a nothing % chance the proportion of adults in the country aged 18 and older who have donated blood in the past two years is between nothing and nothing.

Answer 1

The statistical software output for this problem is:

One sample proportion summary confidence interval:
p : Proportion of successes
Method: Standard-Wald

90% confidence interval results:

Proportion	Count	Total	Sample Prop.	Std. Err.	L. Limit	U. Limit
p	416	2315	0.17969762	0.0079796282	0.1665723	0.19282294

Hence,

a) Point estimate = 0.180

b) 90% confidence interval: (0.167, 0.193)

We are 90% confident the proportion of adults in the country aged 18 and older who have donated blood in the past two years is between 0.167 and 0.193