Answer:
You didn't specify if it was a specific family, so I'll just do my own.
I'm 63 inches, my mother is 65, my Dad is 69, and my sister is 61.
63 + 65 + 69 + 61 = 258
Now to find the average, we take that number and divide it by the number of people.
258/4 = 64.5 inches.