Page 209 - Data Science class 10
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7. Mohan has rupees notes of different denominations. He noted down the number of notes of various
denominations in a table as follows:
Marks 10 20 50 100 500 2000
No. of Notes 20 40 30 10 50 60
Calculate the mode of the above data.
Ans. Notice that 2000 rupee note has highest number. So, the mode is 2000.
8. Create a frequency table for the following:
12 5 4 3 8 9 12 9 8 7
6 71 12 30 2 5 4 3 71 8
7 12 9 6 4 2 1 71 22 3
22 12 8 9 5 12 4 3 12 71
Ans. 12 5 4 3 8 9 12 9 8 7
6 71 12 30 2 5 4 3 71 8
7 12 9 6 4 2 1 71 22 3
22 12 8 9 5 12 4 3 12 71
Element Tally Frequency
1 / 1
2 // 2
3 //// 4
4 //// 4
5 /// 3
6 // 3
7 // 2
8 //// 4
9 //// 4
12 //// // 7
22 // 2
30 / 1
71 //// 4
9. Find the population variance of the following dataset:
3, 5, 5, 6, 6, 7, 8, 10, 10, 10, 12, 15, 20
Ans. Find the mean by adding all data values and divide by the sample size n.
(3 + 5 + 5 + 6 + 6 + 7 + 8 + 10 + 10 + 10 + 12 + 15 + 20)
Mean =
13
= 9
The population variance is:
2 ∑ n ( x – ) m 2
s = i= 1 1
n
2
2
2
2
2
2
2
2
2
2
2
2
= (3–9) +(5–9) +(5–9) +(6–9) +(6–9) +(7–9) +(8–9) +(10–9) +(10–9) +(10–9) +(12–9) +(15–9) +(20–9) 2
13
Practical Questions 207

