3.9 Shortcut Method Formula

Consider the values: 1005, 1010, 1015

If 1000 is subtracted: 5, 10, 15

If again divided by 5: 1, 2, 3

Converted Mean = 2

Original Mean = \(2 \times 5 + 1000=1010\)

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x = 1005, 1010, 1015

• a = 1000
• c = 5
• y = 1, 2, 3
• \(\bar x = 2 \times 5 + 1000=1010 = a+\bar y \times c\)
• \(\bar x = a+\frac{\sum y}{n} \times c\)