Cell phone ownership: 2000 versus 2004.
Refer to Exercise 8.41 (page 517). The estimated proportion of undergraduates owning a phone in 2000 was 43%. We want to test whether the proportion of undergraduate cell phone owners has more than doubled in the last 4 years.
(a) Compute the quantity pˆ 1 - 2pˆ 2 where pˆ 1 is the 2004 estimate and pˆ 2 is the 2000 estimate.
(b) Using the rules for variances, compute the standard error of this estimate.
(c) Compute the z statistic and P-value. What is your conclusion at the 5% level?