Answer:
a. 0.785
Step-by-step explanation:
The sample proportion (Sp) of completed surveys is given by the ratio of families that completed the survey (C) to the total number of families selected to participate in the survey of life attitudes (N).
[tex]S_P=\frac{C}{N} =\frac{628}{800}\\S_P=0.785[/tex]
The sample proportion of completed surveys is 0.785