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The mean and standard deviation of 100 i...

The mean and standard deviation of 100 items are 50, 5 and that of 150 items are 40,6 repectively
What is the variance of all the 250 items

A

50.6

B

53.3

C

55.6

D

59.3

Text Solution

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The correct Answer is:
C
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PUNEET DOGRA-STATISTICS-PRE YEAR QUESTIONS
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  2. The mean and standard deviation of 6 observations are 8 and 4 respecti...

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  3. The mean and standard deviation of 100 items are 50, 5 and that of 150...

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  4. if the regression coefficient of Y on X is4/3,then the regression coef...

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  5. The mean of 20 observations is 15. On checking, it was found that two ...

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  6. The arithmetic mean of the square of the first n natural number is. (...

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  7. Consider the following statements I. Both the regression coefficien...

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  8. Which one of the following measures is determined only after the const...

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  9. BOD is measure of

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  10. What is the variance of first 11 natural numbers?

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  11. Consider the following statements in respect of histogram. I. The al...

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  12. Consider the following statements in respect of a histogram: 1. The ...

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  13. The variance of 20 observations is 5. If each observation is multiplie...

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  14. The marks obtained by 13 students in a test are 10, 3, 10, 12. 9. 7. 9...

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  15. Consider the following statements: I Both variance and standard devi...

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  16. Variance is always independent of the change of

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  17. The standard deviation of the observations 5, 5,5,5,5 is

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  18. Consider the following frequency distribution If the total of ...

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  19. The average marks obtained by the students in a class are 43. If the a...

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  20. If two lines of regression are perpendicular, then the correlation coe...

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