Answer:
A. No, this is not a valid inference because he asked only 30 families
Step-by-step explanation:
Total families in Jack's neighborhood = 60
Random sample is drawn of 30 families.
Out of 30 families, 12% families would help organize the party.
Now Jack claims that 12% of the neighborhood families would be expected to help organize the party.
This inference is not valid because Jack estimated wrongly. He surveyed 30 families and 12% out of 30 and not 60 families are ready to participate.
He should have inferred that 24% of 60 families are ready to participate.