Dentist Visits. The National Center for Health Statistics publishes information about visits to the dentist in National Health Interview Survey. Here is a joint probability distribution for the length of time (in years) since last visit to a dentist or other dental health professional, by age, for U.S. adults during one year. Time (yr)

Age (yr)

18–44 45–64 65–74 75+

A1 A2 A3 A4 P(Ti)

Less than 0.5 0.221 0.154 0.038 0.028 0.441 T1 0.5–under 1 0.101 0.052 0.011 0.011  0.175 T2 1–under 2 0.076 0.036 0.008 0.006 0.126 T3 2–under 5 0.070 0.034 0.010 0.008 0.122 T4 5 or more 0.058 0.038 0.018 0.022 0.136 T5 P(Aj) 0.526 0.31 0.085 0.075 1.000 For a U.S. adult selected at random, determine the following probabilities and interpret your results in terms of percentages.

a. P(T1)

b. P(not A2)

c. P(A4 & T5)

d. P(T4 | A1)

e. P(A1 | T4)