Question -
Answer -
First, we have toarrange the given marks in ascending order.
= 1, 2, 2, 3, 4, 4, 4,5, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 8, 9
Now, we will draw thefrequency table of the given data.
| Marks | Tally Marks | Frequency |
| 1 | 
| 1 |
| 2 | 
| 2 |
| 3 |
| 1 |
| 4 | 
| 3 |
| 5 | 
| 5 |
| 6 | 
| 4 |
| 7 |
| 2 |
| 8 |
| 1 |
| 9 |
| 1 |
(i) By observing thetable clearly, the highest number among the given data is 9.
(ii) By observing thetable clearly, the lowest number among the given data is 1.
(iii) We know that,Range = Highest value – Lowest value
= 9 – 1
= 8
(iv) Now we have tocalculate Arithmetic Mean,
Arithmetic mean = (Sumof all observations)/ (Total number of observation)
Then,
Sum of all observation= 1 + 2 + 2 + 3 + 4 + 4 + 4 + 5 + 5 + 5 + 5 + 5 + 6 + 6 + 6 + 6 + 7 + 7
+ 8 + 9
= 100
Total Number of Observation= 20
Arithmetic mean =(100/20)
= 5