$1000$ families with $2$ children were selected randomly,and the following data were recorded:

Number of girls in a family	$0$	$1$	$2$
Number of families	$128$	$672$	$200$

Compute the probability of a family,chosen at random,having $(1)$ two girls,$(2)$ one girl.

(N/A) The total number of families is $1000$.
$(1)$ Let $E_1$ be the event that the chosen family has $2$ girls.
The number of families having $2$ girls is $200$.
Probability $P(E_1) = \frac{\text{Number of families with } 2 \text{ girls}}{\text{Total number of families}} = \frac{200}{1000} = 0.2$.
$(2)$ Let $E_2$ be the event that the chosen family has $1$ girl.
The number of families having $1$ girl is $672$.
Probability $P(E_2) = \frac{\text{Number of families with } 1 \text{ girl}}{\text{Total number of families}} = \frac{672}{1000} = 0.672$.