A dental hygienist is a health-care professional who works alongside a dentist to meet the oral health care needs of patients. Asked by one of her clients who needs to get a cavity filled what the average number of cavities a person gets filled by the time they are 50 years old, the hygienist responds that she will gather and determine not just the average, but also the median and the mode - because she would like to know this information herself. A bit of research turns up the following data table taken from a research project of a graduate student. The graduate student surveyed 20 people aged 50 from around Idaho. Patient ID# Cavities Filled
1 1
2 8
3 7
4 9
5 11
6 12
7 7
8 5
9 2
10 0
11 8
12 9
13 7
14 6
15 8
16 9
17 8
18 9
19 8
20 8

a. What is the mean (average) number of cavities a person gets filled by age 50?
b. What is the median number of cavities a person gets filled by age 50?
c. What is the most often an occurring number of cavities filled in this data set?