#### Descriptive Statistics and Probability Book Back Questions

11th Standard

Reg.No. :
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Time : 00:45:00 Hrs
Total Marks : 30
5 x 1 = 5
1. When calculating the average growth of economy, the correct mean to use is?

(a)

Weighted mean

(b)

Arithmetic mean

(c)

Geometric mean

(d)

Harmonic mean

2. When an observation in the data is zero, then its geometric mean is

(a)

Negative

(b)

Positive

(c)

Zero

(d)

Cannot be calculated

3. The best measure of central tendency is

(a)

Arithmetic mean

(b)

Harmonic mean

(c)

Geometric mean

(d)

Median

4. Median is same as

(a)

Q1

(b)

Q2

(c)

Q3

(d)

D2

5. The median of 10,14,11,9,8,12,6 is

(a)

10

(b)

12

(c)

14

(d)

9

6. 3 x 2 = 6
7. A die is thrown twice and the sum of the number appearing is observed to be 6. What is the conditional probability that the number 4 has appeared at least once?

8. A die is thrown. Find the probability of getting
(i) a prime number
(ii) a number greater than or equal to 3

9. Let P(A)=$\frac{3}{5}$ and P(B)=$\frac{1}{5}$ . Find P(A∩B) if A and B are independent events.

10. 3 x 3 = 9
11. Daily income (in Rs) of ten families of a particular place is given below. Find out GM
85, 70, 15, 75, 500, 8, 45, 250, 40, 36

12. A factory has 3 machines A1, A2, A3 producing 1000, 2000, 3000 screws per day respectively. A1 produces 1% defectives, A2 produces 1.5% and A3 produces 2% defectives. A screw is chosen at random at the end of a day and found defective. What is the probability that it comes from machines A1?

13. Calculate the mean deviation about median and its relative measure for seven numbers given below: 55, 45, 40, 20, 60, 80, and 30.

14. 2 x 5 = 10
15. Compute Quartile deviation from the following data

 CI 10-20 20-30 30-40 40-50 50-60 60-70 70-80 f 12 19 5 10 9 6 6
16. Find out the coefficient of mean deviation about median in the following series

 Age in years No. of persons 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 8 12 16 20 37 25 19 13