1. In the Second Avenue School, the 71 pupils with measles had 93 brothers and sisters at home. Of the 93, 21 developed measles. What was the secondary attack rate in the brothers and sisters? (Percent)
2. In the Second Avenue School District, the 71 pupils with measles had 93 brothers and sisters at home. Of these, 51 siblings were in what would be classified as the "lower" socioeconomic group. The rest were in the "middle" and "upper" socioeconomic groups. Of the 21 cases of measles in these 93 children, 5 were in the "middle" and "upper" socioeconomic groups.

Calculate the following:

(a)The attack rate among the "Middle & Upper" group.

(b)The attack rate among the "Lower" group.