Question

1800 families with 2 children were selected randomly and the following data were recorded:

No. of girls in a family	2	1	0
No. of families	700	850	250

Computer the probability of a family chosen at random having: 2 girls

Answer 1

Total number of families n(S) = 1800.
Event = {2 girls}
n(E) = 700
P(E) = ?

∴ P(E) = `"n(E)"/"n(S)" = 700/1800 = 7/18`.