A researcher wants to estimate the proportion of a population which possesses a given characteristic.A random sample of size 250 is taken and 40% of the sample possesses the characteristic.The 90% confidence interval to estimate the population proportion is ___.
A)0.35 to 0.45
B)0.34 to 0.46
C)0.37 to 0.43
D)0.39 to 0.41
E)0.40 to 0.45

Question

Quizplus · Accepted Answer

The 90% confidence interval for the population proportion is 0.4 +/- 1.645 * sqrt(0.4 * 0.6 / 250) = 0.4 +/- 0.05 = 0.35 to 0.45.

A Researcher Wants to Estimate the Proportion of a Population