6. Many celebrities and public figures have Twitter accounts with large numbers of followers. However, some of these followers are fake, resulting from accounts generated by spamming computers. In a sample of 85 twitter accounts, the proportion of fake followers was .171 (about 17.1%). Construct a 95% confidence interval for the proportion of fake twitter followers using the steps below:

a) Find the critical value Za/2 " that corresponds to a 95% confidence level.

b) Calculate "E"

c) Construct your confidence interval.

d) Write sentence that explains the meaning of the confidence interval. I am 95% confident that...

e) A Twitter executive claims the percentage of fake Twitter followers around 12%. Does your confidence interval support their claim or contradict this claim?

7. In a sample of 35 children, the mean age at which the first began to combine words (use 2 to 3 words at a time) was 16.51 months with a standard deviation of 9.59 months. Construct a 95% confidence interval for the mean age which children first begin to combine words using the steps below.

a) Find the critical value ta/2 " that corresponds to a 95% confidence level and a sample size of 35.

b) Calculate "E"

c) Construct your confidence interval.

d) Write sentence that explains the meaning of the confidence interval. I am 95% confident that...