The primary aim of a study by Carter et al. (A1) was to investigate the effect of the age at onset of bipolar disorder on the course of the illness. One of the variables investigated was family history of mood disorders. Table 3.4.1 shows the frequency of a family history of mood disorders in the two groups of interest (Early age at onset defined to be 18 years or younger and later age at onset dened to be later than 18 years). Table 3.4.1: Frequency of a family history of mood disorder by age group among bipolar subjects Family history of mood disorders Early =18 (E) Later > 18 (L) Total Negative (A) 28 35 63 Bipolar disorder (B) 19 38 57 Unipolar (C) 41 44 85 Unipolar and bipolar (D) 53 60 113 Total 141 177 318 Suppose we pick a person at random from this sample: a What is the probability that this person will be an Early age of onset subject (E) or will have no family history of mood disorders (A) or both? b What is the probability that this person will be later than 18 years? c- What is the probability that this person will be 18 years old or younger? d- Suppose we pick a subject at random from the 318 subjects and nd that he is 18 years or younger (E). What is the probability that this subject will be one who has no family history of mood disorders (A)? e- What is the probability that a person picked at random from the 318 subjects will be Early (E) and will be a person who has no family history of mood disorders (A)