Over half of all American teens ages 12 to 17 years have an

Over half of all American teens (ages 12 to 17 years) have an online profile, mainly on Facebook. A random sample of 464 teens with profiles found that 315 included photos of themselves.

(a) Give the 90% large-sample confidence interval for the proportion p of all teens with profiles who include photos of themselves.
Large-sample Interval: _________ to _________________

(b) Give the plus four 90% confidence interval for p . (The plus-four interval always pulls the results away from 0% or 100%, whichever is closer. Even though the condition for using the large-sample interval is met, the plus four interval is more trustworthy.)
Plus four Interval: ___________ to ___________________

Solution