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Zorluk: OrtaMeasures of Central Tendency

The monthly revenue collection (in millions of Naira, ₦’million\text{₦'million}) from six regional revenue offices of a state government was recorded as 1414, 1818, 1212, xx, 2222, and 1616. If the arithmetic mean of the revenue collected across all six offices is 17 million\text{₦}17\text{ million}, what is the value of xx?

Cevap: 20 million Naira

Cevap

The value of xx is 20 million Naira20\text{ million Naira} (or simply 2020).
The arithmetic mean is defined as xˉ=xn\bar{x} = \frac{\sum x}{n}. For n=6n = 6 offices with a mean of 17 million17\text{ million}, the total sum must be 6×17=102 million6 \times 17 = 102\text{ million}. Summing the known values gives 14+18+12+22+16=8214 + 18 + 12 + 22 + 16 = 82. Subtracting 8282 from 102102 yields x=20 million Nairax = 20\text{ million Naira}.

Adım Adım Çözüm

1
Calculate the sum of all observations in terms of xx
Sum =14+18+12+x+22+16=82+x= 14 + 18 + 12 + x + 22 + 16 = 82 + x
The mean formula requires the total sum of all values divided by the number of observations.
2
Set up the mean equation using xˉ=xn\bar{x} = \frac{\sum x}{n}
82+x6=17\frac{82 + x}{6} = 17$
The question specifies that the arithmetic mean across the 6 regional offices is 17.
3
Solve for the unknown value xx
82 + x = 102 \implies x = 20$
Subtracting the sum of the five known values (82) from the total required sum (102) yields the missing observation.

Anahtar Kavram

Calculation of a Missing Value from the Arithmetic Mean
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