A sociologist was curious about how much smartphone access has changed for American teenagers. They obtained separate random samples of teenagers from 2017 and 2013. Here are their results:
Has access to smartphone?
2017
2013
Yes
450
120
No
150
280
Total
600
400
They want to use these results to construct a 95% confidence interval to estimate the difference in the
proportion of teens each year who had access to a smartphone (p2017 - P2013). Assume that all of the
conditions for inference have been met.
Which of the following is a correct 95% confidence interval based on their data?