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Solution
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Solution provided by AtoZmath.com
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Combined mean and Combined Standard deviation calculator
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1. Find the combined Standard Deviation from the following data.
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A |
B |
number of Observations |
40 |
60 |
Average |
10 |
15 |
S.D. |
1 |
2 |
2. Find the combined Standard Deviation from the following data.
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A |
B |
number of Observations |
100 |
150 |
S X |
25000 |
42000 |
Variance |
100 |
40.96 |
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Example1. Find Combined Mean from the following data `N_1=40,bar X_1=10` `N_2=60,bar X_2=15`
Solution: Combined Mean : `bar x_12 = ( N_1 * bar (x)_1 + N_2 * bar (x)_2 )/( N_1 + N_2 )`
`bar x_12 = ( 40 * 10 + 60 * 15 )/( 40 + 60 )`
`bar x_12 = ( 400 + 900 )/(100)`
`bar x_12 = 1300/100`
`bar x_12 = 13`
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