Use the following for the next five exam questions: Your instructor, Kelsi, got their first phone at the age of 14 (it was one of those older phones with a retractable antenna that you had to buy and load minutes onto). Having personal cell phones in the US has become increasingly more common, so Kelsi wants to estimate the average age at which all ST 201 students get their first phone. Kelsi took a random sample of fifty ST 201 students and found that the average age in the sample was 13.92 years. Suppose the age is known to vary on average by 2.61 years (think "standard deviation"). Data updated 3/12 Age received first cell phone 12 10 8 Frequency 6 ONA 10 11 12 13 14 15 16 17 18 19 20 age (in years)