A data set consists of values {10, 20, 30, 40} with corresponding frequencies {f1, f2, f3, f4}. The mean of this data set is M.
If the frequency f1 (for value 10) increases by 5, and the frequency f4 (for value 40) decreases by 5, while f2 and f3 remain unchanged, which of the following statements must be true about the new mean (M')?
M' ＞ M
M' \lt M
M' = M
The relationship between M' and M cannot be determined without specific values for f1, f2, f3, f4.
