A one-sided confidence interval for p can be written as $p

Question

A one-sided confidence interval for p can be written as $p < \hat { p } + \mathrm { E } \text { or } p < \hat { p } - \mathrm { E }$ E where the margin of error E is modified by replacing $z _ { \alpha / 2 }$ with ${ } ^ { Z } \alpha$ . If a teacher wants to report that the fail rate on a test is at most x with 90% Confidence, construct the appropriate one-sided confidence interval. Assume that a simple random sample of 74 students results in 8 who fail the test. 
A) $p < 0.167$
B) $p < 0.062$
C) $p < 0.154$
D) $p > 0.062$

Quizplus · Accepted Answer

The sample proportion $\hat{p}$ is 8/74. For a 90% one-sided confidence interval, use $z_{0.10}$ (approximately 1.28) to calculate the margin of error and construct the interval.

A One-Sided Confidence Interval for P Can Be Written As p