Ok
Moving on I found this question
And before I came to the forum I wanted to see if I could do it myself and after sitting here for half an hour I have had no luck
Please help
Telling me the answer is 8 but I dont know how
Hi there!
Ok so in order to see how many plants were actually sold in the week, we would require a cumulative frequency column, which will thus allow us to work out how on earth they got that mean.
So:
Cumulative frequency column (Number of plants purchased column x Frequency column)
8
38
3x
44
20
Total = 110 + 3x
The total of the frequency column in 42 + x
In this question, the person calculated the mean by dividing the sum of cumulative frequency column BY the sum of the frequency column
So, we would just solve for x using algebra, since we know what the mean already is.
(110 + 3x) / (42 + x) = 2.68
--> (110 + 3x) / 2.68 = (42 + x)
Times both sides by 2.68 to get rid of the fraction =
--> 110 + 3x = 2.68(42 +x)
Expand the brackets
--> 110 + 3x = 112.56 + 2.68x
Minus 110 from both sides
--> 3x = 2.56 + 2.68x
Minus -2.68x from both sides
--> 0.32x = 2.56
Solve for x
--> 0.32x / 0.32 = 2.56 / 0.32
= 8
I hope that made sense!!