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The number of observation in a group is ...

The number of observation in a group is 40. If the average of first 10 is 4.5 and that of the remaining 30 is 3.5, then the average of the whole group is

A

`(1)/(5)`

B

`(15)/(4)`

C

6

D

8

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The correct Answer is:
B
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AAKASH SERIES-MEASURES OF DISPERSION (STATISTICS)-Exercise - I
  1. Mean of the numbers 1,2,3,…,n with respective weights 1^(2) + 1, 2^(...

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  2. The mean of n items is bar(x). If the first item is increased by 1, se...

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  3. The number of observation in a group is 40. If the average of first 10...

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  4. Mean of a set of numbers is bar(x). If each number is increased by lam...

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  5. The median of 5,19,14,6,8,9,12,13,21 is

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  6. The median of a set of 9 distinct observations is 20.5. If each of the...

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  7. Median of (x)/(5), x, (x)/(4), (x)/(2), (x)/(3) is 8. If x gt 0 then v...

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  8. The mean and median of 100 items are 50 and 52 respectively. The value...

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  9. Mode of the data 3,2,5,2,3,6,6,5,3,5, 2, 5 is

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  10. Mode of the following distribution is

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  11. If the difference between mean and mode is 63, then difference between...

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  12. If the mode of the data 25,15,20,25,18,14,15,18,16,20,25,20,x,18 is 25...

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  13. A data consists of two 2's, four 4's, six 6's three 8s', and 10. Then ...

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  14. The average value of the median of 2,8,3,7,4,6,7 and the mode of 2,9,3...

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  15. Geometric mean of 2, 2^(2), 2^(3),…,2^(n) is

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  16. If the Geometrical mean of x, 16, 50 is 20, then the value of x is

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  17. The reciprocal of the mean of the reciprocals of n observations is

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  18. The Harmonic mean of the numbers 2,3,4 is

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  19. If A.M. = 24.5, G.M. 24.375 then H.M. =

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  20. In problems on speed of a body, the average used is

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