An economist conducted a study to identify the percentage of family income allocated to the purchase of groceries. She surveyed a random sample of 50 families and compiled the following numeric frequency distribution:
|
Percent of income
|
Number of families
|
|
10 - under 20%
|
6
|
|
20 - under 30%
|
14
|
|
30 - under 40%
|
16
|
|
40 - under 50%
|
10
|
|
50 - under 60%
|
4
|
(a) Compute and interpret the (approximate) mean percentage of family income allocated to grocery purchase. (Hint: Use the weighted average formula with the midpoint of each interval as xi.)
(b) What is the maximum percentage of income that is allocated to grocery purchase by:
(i) the lower 50% of families?
(ii) the lower 25% of families?
(c) 25% of families spend more than a specific percentage of their income on groceries. What is that percentage of income value?