Answer:
Here we have the table for the 8 students that said yes.
a) Out of the 8 students, 5 purchased their favorite food more than four times a month.
The proportion will be p = 5/8, and this can not be simplified anymore because 5 is a prime number and 5 is not a factor of 8.
b) The mean time will be equal to the amount of each of the 8 purchased their favourite food divided by the total sample (8)
This is:
m = (6 + 4 + 3 + 8 +6 + 9 + 4 + 7)/8 = 5.875
c) Out of a sample of 20, 8 buy lunch regularly, this is; p1 = 8/20
The amount of students that regularly buy food will be:
p1*1000 = (8/20)*1000 = 400
And of those 400, 5/8 buy their favourite lunch more than 4 times per month:
(5/8)*400 = 250
d: The mean number of times that a student regularly buys salad.
We have 3 students that regularly buy salad (so we only do the math with those 3)
The mean is (8 + 6 + 7)/3 = 7
So for the students that regularly buy salad, the mean of times that the buy salad in a month is 7 times.