#### Statistics Book Back Questions

9th Standard

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Maths

Time : 00:45:00 Hrs
Total Marks : 30
4 x 1 = 4
1. Data available in an unorganized form is called ------------- data

(a)

Grouped data

(b)

class interval

(c)

mode

(d)

raw data

2. Let m be the mid point and b be the upper limit of a class in a continuous frequency distribution. The lower limit of the class is

(a)

2m - b

(b)

2m+b

(c)

m-b

(d)

m-2b.

3. The algebraic sum of the deviations of a set of n values from their mean is

(a)

0

(b)

n-1

(c)

n

(d)

n+1

4. If the mean of five observations x, x+2, x+4, x+6, x+8, is 11, then the mean of first three observations is

(a)

9

(b)

11

(c)

13

(d)

15

5. 2 x 2 = 4
6. Find the mode for the set of values 17, 18, 20, 20, 21, 21, 22, 22.

7. A set of numbers consists of five 4’s, four 5’s, nine 6’s,and six 9’s. What is the mode.

8. 4 x 3 = 12
9. The following data gives the number of residents in an area based on their age. Find the average age of the residents

 Age Number of Residents 0-10 10-20 20-30 30-40 40-50 50-60 2 6 9 7 4 2
10. The arithmetic mean of 6 values is 45 and if each value is increased by 4, then find the arithmetic mean of new set of values

11. The mean weight of 4 members of a family is 60kg.Three of them have the weight 56kg, 68kg and 72kg respectively. Find the weight of the fourth member

12. Find the median of the given values : 47, 53, 62, 71, 83, 21, 43, 47, 41.

13. 2 x 5 = 10
14. Calculate the median for the following data:

 Height (cm) No. of Students 160 150 152 161 156 154 155 12 8 4 4 3 3 7
15. n a distribution, the mean and mode are 66 and 60 respectively. Calculate the median.