Question

Out of a sample of 180 students, 85 indicated that they preferred chocolate ice cream to vanilla ice cream.

a. Estimate the value of the population proportion of those who preferred chocolate ice cream. (Round the final answer to 3 decimal places.)

Estimated population proportion   

b. Compute the standard error of the proportion. (Round the final answer to 4 decimal places.)

Standard error of the proportion   

c. Determine a 80% confidence interval for the population proportion of those who preferred chocolate ice cream. (Round the final answers to 3 decimal places.)

Confidence interval for the population proportion is between ？and ？

d. Interpret your findings.    

If 180 such intervals were determined, the population ？ would be included in about  Not attemptedintervals.

Answer 1

a. Population proportion of those who preferred chocolate ice cream

b. Standard error is

c. z value for 80% CI is 1.282 as P(-1.282<z<1.282)=0.80

So Margin of Error is

Hence CI is

d. Population parameter will lie in the range of 0.424 to 0.520

If 180 such intervals were determined, the population parameter would be included in (0.424, 0.520).