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The calculated mean of 50 observations was 80. It was later discovered that observation 19 was recorded by mistake as 91. What was the correct mean? - Algebra

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प्रश्न

The calculated mean of 50 observations was 80. It was later discovered that observation 19 was recorded by mistake as 91. What was the correct mean?

योग
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उत्तर

Mean = `"The sum of all observations"/"Total number of observations"`

∴ The sum of all observations = Mean x Total number of observations 

∴ The sum of 50 observations = 80 x 50

= 4000

Sum of observations after correction = 4000 + 19 – 91

= 3928 

∴ Corrected mean = `"Sum of observations after correction"/"Total number of observations"`

= `3928/50`

 = 78.56

∴ The corrected mean is 78.56.

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अध्याय 7: Statistics - Practice set 7.5 [पृष्ठ १२५]

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बालभारती Mathematics 1 [English] Standard 9 Maharashtra State Board
अध्याय 7 Statistics
Practice set 7.5 | Q (7) | पृष्ठ १२५

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