Question

These are the profits of food companies:
Profits (interval) Number of companies (freq)
140-159 7
160-179 30
180-199 13
What's the average deviation?

Answer 1

standard deviation?

Answer 2

Yes

Answer 3

Mean(x) = [(7*150) + (30*170) +(13*190)]/50
Mean(x^2) = [(7*150^2) + (30*170^2) +(13*190^2)]/50

standard deviation = sqrt[Mean(x^2) - Mean(x)^2]

Answer 4

Okay, thanks