There are 50 numbers. Each number is subtracted from 53 and the mean of the
numbers so obtained is found to be –3.5. The mean of the given numbers is :
(A) 46.5 (B) 49.5 (C) 53.5 (D) 56.5
The mean of 100 observations is 50. If one of the observations which was 50 is
replaced by 150, the resulting mean will be :
(A) 50.5 (B) 51 (C) 51.5 (D) 52
If each observation of the data is increased by 5, then their mean
(A) remains the same (B) becomes 5 times the original mean
(C) is decreased by 5 (D) is increased by 5
The mean of five numbers is 30. If one number is excluded, their mean becomes
28. The excluded number is :
(A) 28 (B) 30 (C) 35 (D) 38
A grouped frequency distribution table with classes of equal sizes using 63-72(72 included) as one of the class is constructed for the following data :
30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88,
40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96,
102, 110, 88, 74, 112, 14, 34, 44.
The number of classes in the distribution will be :
(A) 9 (B) 10 (C) 11 (D) 12
A grouped frequency table with class intervals of equal sizes using 250-270 (270 not included in this interval) as one of the class interval is constructed for the following data :
268, 220, 368, 258, 242, 310, 272, 342,
310, 290, 300, 320, 319, 304, 402, 318,
406, 292, 354, 278, 210, 240, 330, 316,
406, 215, 258, 236.
The frequency of the class 310-330 is:
(A) 4 (B) 5 (C) 6 (D) 7
n the class intervals 10-20, 20-30, the number 20 is included in :
(A) 10-20 (B) 20-30
(C) both the intervals (D) none of these intervals
The class marks of a frequency distribution are given as follows :
15, 20, 25, …
The class corresponding to the class mark 20 is :
(A) 12.5 – 17.5 (B) 17.5 – 22.5 (C) 18.5 – 21.5 (D) 19.5 – 20.5
Let m be the mid-point and l be the upper class limit of a class in a continuous
frequency distribution. The lower class limit of the class is :
(A) 2m + l (B) 2m – l (C) m – l (D) m – 2l
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