Suppose that on January 1, 1987, a man is 50 years old, that he will live for 30 more years (until 2016), and that the rate of tooth loss over this 30-year period is the same as in 1987. If a man has 13 teeth remaining on January 1, 1987, what is the probability he will need dentures (have 10 or fewer teeth remaining) during his 30-year lifetime?

Dentistry
The data in Table 4.20 were reported by men in the Health Professionals Follow-up Study on the number of teeth lost over a 1-year period (January 1, 1987, to December 31, 1987).

Table 4.20: Distribution of number of teeth lost from January 1, 1987, to December 31, 1987, among 38,905 men in the Health Professionals Follow-up Study

Number of teeth lost ___________________ Frequency
0 ....................................................................... 35,763
1 ..........................................................................1,978
2 ............................................................................ 591
3 ............................................................................ 151
4 ............................................................................ 163
5−9 ........................................................................ 106
10+ ........................................................................ 153
Total ................................................................ 38,905