X-Git-Url: https://code.communitydata.science/stats_class_2020.git/blobdiff_plain/efa6913590499d105277c2907cde2a96aa7bd51f..f79b3ace181536090eb8fbedfaa3a887ac028ac6:/os_exercises/ch5_exercises_solutions.rmd diff --git a/os_exercises/ch5_exercises_solutions.rmd b/os_exercises/ch5_exercises_solutions.rmd index 5965223..334cb9a 100644 --- a/os_exercises/ch5_exercises_solutions.rmd +++ b/os_exercises/ch5_exercises_solutions.rmd @@ -57,7 +57,7 @@ SE = \sqrt{\frac{p(1-p)}{n}}\\ \phantom{SE} = 0.0177 \end{array}$$ -# 5.8 Twitter users and news, Part I +# 5.8 Twitter users & news I The general formula for a confidence interval is $point~estimate~±~z^*\times~SE$. Where $z^*$ corresponds to the z-score for the desired value of $\alpha$. @@ -70,7 +70,7 @@ $$95\% CI = (45.8\%, 58.2\%)$$ Which means that from this data we are 99% confident that between 45.8% and 58.2% U.S. adult Twitter users get some news through the site. -# 5.10 Twitter users and news, Part II +# 5.10 Twitter users & news II (a) False. See the answer to exercise 5.8 above. With $\alpha = 0.01$, we can consult the 99% confidence interval. It includes 50% but also goes lower. A null hypothesis of $p=0.50$ would not be rejected at this level.