Mathematics
The mean of 20 numbers is 18. If 3 is added to each of the first ten numbers, find the mean of new set of 20 numbers.
Measures of Central Tendency
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Answer
Mean =
∴ Sum of observations = Mean × No. of observations
⇒ Sum of observations = 18 × 20 = 360.
Since 3 is added to first ten numbers then total sum increases by 10 × 3 = 30.
New sum = 360 + 30 = 390.
Mean = = 19.5
Hence, the mean of new set of 20 numbers is 19.5
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