Constructing a Confidence Interval for the Population Proportion
The Berkman center for Internet and Society at Harvard recently conducted a study analyzing the privacy management habits of teen Internet users. In a group of 50 teens, 13 reported having more than 500 friends on Facebook. Use the “plus four” method to find a 90% confidence interval for the true proportion of teens who would report having more than 500 Facebook friends. Work toward the required confidence interval by providing the information below.
Confia«* 1«V*I Ar«* in On« Tail Z-SCOf*
025
80V, 0.« 1282
90S 005 IMS
95% 0 025 196
98% 0.1 2326
99% 0 005 2576
(Include three decimal places below)
a. p
b. a | o *
C. Z0.05 = «ms ?
d. EBP = moo? ??
e. We are 90% confident that the true proportion
is above |a»y *]
f. We are 90% confident that the true proportion
is below 0170? ?kJ
g. Suppose the researchers from the previous
problem wanted to reduce their EBP by 50%. What sample size would be needed? Assume p ‘ is the same, n = ^ « (Round
to the nearest whole number)
