In a survey of her introductory statistics class, an instructor found the average number of Facebook friends the 49 respondents had was 539.2 and the standard deviation was 298. The data on number of Facebook friends are not strongly skewed.
a. Identify the observational unit for this study.
b. Identify the variable of interest and whether it is categorical or quantitative.
c. In the context of this study, explain why it is valid to use the theory-based (t-distribution) approach to find a confidence interval?
d. Use the Theory-Based Inference applet to find and report a 95% confidence interval for the parameter of interest. Also, interpret the interval in the context of the study.