According to recent data by the American Marketing Association, 78.6% of people in the 18–24 age group used Snapchat in 2017. You want to find out what the Snapchat penetration is among your classmates who are all between 18 and 24 years old. Suppose you obtain a random sample of 260 students and find that 203 students in this sample are active Snapchat users.

a. Construct a 90% confidence interval to estimate the actual proportion of Snapchat users.

b. What is the margin of error for this sample?

c. Is there evidence that this proportion matches that of the overall population based on the sample?