Researchers were curious if different regions of the country differed in their use of a new, popular, social media app. Two independent random samples were taken. One sample from a city on the west coast of America and another from the east coast. College students aged 18-25 were asked if they have used the app. Their responses are organized in a table and graph below.

West Coast East Coast Total

Yes: 123 270 393

No: 98 153 251

Total: 221 423 644

a.) Does there appear to be an association between which coast a student is from and whether or not they have used this social media app? (Note: Do not answer this question using an inference procedure.)

Hint: An association with differences on either table, frequencies, %'s, or graph required.

b.) What is the probability that a randomly selected student is from the west coast, given that this student has used the social media app?

c.) A curious statistics student wants to test if the proportion of students who have used the app is greater on the East Coast than on the West Coast. Write the appropriate null and alternative hypotheses for this hypothesis test.

d.) The P-value for the hypothesis test is 0.022. Based on this p-value, what conclusion should the researcher make?

e.) In another study, college students on the East Coast were compared with 85 students in the Midwest and p-value of 0.13 was found. However, there is concern that a Type II has been made. Describe how a different sample size would decrease the likelihood of a Type II error and how that would affect your standard deviation for your sampling distribution.