# Statistics – Class 9 /Maths.

Chapter 14 of NCERT/CBSE Class 9 Maths is about Statistics. Herein this lesson you can find out practice problems for this chapter.

CBSE CLASS 9 MATHEMATICS
Statistics – Chapter 14 / Sample paper.
Fill in the blanks:

1. Facts or figures collected with a definite purpose are called ————
2. The area of study dealing with the presentation, analysis and interpretation of data is ————–
3. Which is the most frequently occurring observation?
4. The class mark of the class 20-30 is ———–
5. The range of the data 25, 23, 20, 29, 38, 40, 45, 50 is —————-
6. Find the mean of first 10 prime numbers?
7. If the mean of the following observations x, x-2, x-4, x-5, x+11 is 10, then find the value of x?
8. Arithmetic mean of terms 55, 52, 59, x, 60 is 50. Find the value of x?
9. Find the median of first five prime numbers?
10. Find the mode of the following marks (out of 10) obtained by 20 students:
4,6,5,9,3,2,7,7,6,5,4,9,10,10,3,4,7,6,9,9.
11. The following observations have been arranged in ascending order. If the median of the data is 63, find the value of x?
29, 32, 48, 50, x, x + 2, 72, 78, 84, 95.
12. The following number of goals was scored by a team in a series of 10 matches: 2, 3, 4, 5, 0, 1, 3, 3, 3, 4, 3. Find the mean, median and mode of the scores?
13. Find the mean of first 5 multiples of 5?
14. The mean of x and y is 10 and Mean of x, y and z is 15. Find the value of z?
15. Find the mode of 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14, 18.

1. Data
2. Statistics
3. Mode
4. 25
5.30
5. Mean = Sum of all observations/ Total number of observations
= 2+3+5+7+11+13+17+19+23+29/10
= 129/10
= 12.9
6. Given mean = 10
x + x -2 + x – 4 + x – 5 + x+ 11/5 = 10
5x/5 = 10
x = 10.
7. Given mean = 50
55 + 52 + 59 + x + 60 /5 = 50
226 + x = 250
x = 250 – 226 = 24
8. First 5 prime numbers are 2, 3, 5, 7 and 11.These numbers are in ascending order. So median = 5
9. Here 9 occurs most frequently, i.e., 4 times.
So the mode is 9.
10. Given Median = 63
So (x + x + 2)/2 = 63
2x + 2 = 126
2x = 126 – 2 = 124
x = 124/2 = 62.
11. Mean = 2 + 3 + 4+ 5 + 0 + 1+ 3 + 3 + 4 + 3/10
= 28/10 = 2.8.
Mode = 3 (occurs 4 times)
To find Median, arrange the numbers in ascending order:
0, 1, 2, 3, 3, 3, 3, 4, 4, 5
Median = (3 + 3)/2 = 6/2 = 3
12. Multiples of 5 are 5, 10, 15, 20, and 25.
Mean = (5 + 10 + 15 + 20 + 25)/5 = 75/5 = 15.
13. Given (x + y) /2= 10
x + y = 20
Also (x + y + z)/3= 15
x + y + z = 45
20 + z = 45
z = 45 – 20 = 25.
14. Mode = 14, because 14 occurs 4 times.