2:41 PM - O @+ . . 30 Statistics for Busines...Id ( PDFDrive )-1.pdf ~ Read-only . . . OW that, compared with the same period last year, the 101- lowing percentage increases in dollar sales had been achieved over the Christmas period this year: 10.2 3.1 5.9 7.0 3.7 2.9 6.8 7.3 8.2 4.3 Exercises 47 2.8 The ages of a sample of 12 students enrolled in an on- line macroeconomics course are as follows: 21 22 27 36 18 19 ing 22 23 22 28 36 33 ed a. What is the mean age for this sample? b. Find the median age. c. What is the value of the modal age? Application Exercises 2.9 A random sample of 156 grade point averages for students at one university is stored in the ny data file Grade Point Averages. od a. Compute the first and third quartiles. les b. Calculate the 30th percentile. rs) c. Calculate the 80th percentile. of 2.10 A sample of 33 accounting students recorded the number of hours spent studying the course material during the week before the final exam. The data are stored in the data file Study. a. Compute the sample mean. b. Compute the sample median. Its c. Comment on symmetry or skewness. in- d. Find the five-number summary for this data. led 2.11 The data file Sun contains the volumes for a random sample of 100 bottles (237 mL) of a new suntan lotion. a. Find and interpret the mean volume. b. Determine the median volume. ple c. Are the data symmetric or skewed? Explain. O