Answer:
Σ( xi ) / n ; $29
Step-by-step explanation:
Given the following data:
X= $27, $31, $30, $26, $25, $27, $37, $33, $32, $28, $26, $26
Number of observations (n) = 12
Mean formula (m) = ( Σ xi ) / n
Where i = each individual value in X
Mean water bill for the years is thus :
m = Σ [(27 + 31 + 30 + 26 + 25 + 27 + 37 + 33 + 32 + 28 + 26 + 26)] / 12
m = 348 / 12
m = 29
Hence, the mean water bill for the year is $29
Since | x - 4 | < 9, we have -9 < x - 4 < 9.
