SOLUTION: A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 stu

Algebra ->  Probability-and-statistics -> SOLUTION: A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 stu      Log On


   

Question 749084: A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 students are shown below.
YES-18, NO-12
Construct a 98.5% confidence interval for a population proportion who prefer the new alpha-grading system.
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A survey was conducted to determine the percentage of students at a post secondary institution who prefer the new alpha-grading system. The responses from a random sample of 30 students are shown below.
YES-18, NO-12
Construct a 98.5% confidence interval for a population proportion who prefer the new alpha-grading system.
------
Note: 0.985-1 = 0.015
(1/2)0.015 = 0.0075
invNorm(0.0075) = 2.4324
-------------------------------
p-hat = 18/30 = 0.6
ME = 2.4324*sqrt[0.6*0.4/30] = 0.2176
----------------------
98.5% CI: 0.6-0.2176 < P < 0.6+0.2176
==========================================
Cheers,
Stan H.
=============