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प्रश्न
What is primary data?
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उत्तर
The word data means information statistical data and of two types
(i) Primary data, (ii) Secondary data
Primary data: when an investigator collects data himself with a definite plan or design in his (her) mind is called primary data
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संबंधित प्रश्न
What secondary data?
Find the mean, median and mode of the following data:
| Marks obtained | 25 – 35 | 35 – 45 | 45 – 55 | 55 – 65 | 65 – 75 | 75 – 85 |
| No. of students | 7 | 31 | 33 | 17 | 11 | 1 |
A survey regarding the heights (in cm) of 50 girls of a class was conducted and the following data was obtained:
| Height (in cm) | 120 – 130 | 130 – 140 | 140 – 150 | 150 – 160 | 160 – 170 | Total |
| No. of girls | 2 | 8 | 12 | 20 | 8 | 50 |
Find the mean, median and mode of the above data.
The following table gives the daily income of 50 workers of a factory:
| Daily income (in Rs) | 100 – 120 | 120 – 140 | 140 – 160 | 160 – 180 | 180 – 200 |
| No. of workers | 12 | 14 | 8 | 6 | 10 |
Find the mean, median and mode of the above data.
While calculating the mean of a given data by the assumed-mean method, the following values were obtained.
`A = 25, sum f_i d_i = 110, sum f_i = 50`.
Find the mean.
The median of 19 observations is 30. Two more observations are made and the values of these are 8 and 32. Find the median of the 21 observations taken together.
| HINT | Since 8 is less than 30 and 32 is more than 30, so the value of median (middle value) remains unchanged. |
In the following data, find the values of p and q. Also, find the median class and modal class.
| Class | Frequency (f) | Cumulative frequency (cf) |
| 100 – 200 | 11 | 11 |
| 200 – 300 | 12 | p |
| 300 – 400 | 10 | 33 |
| 400 – 500 | q | 46 |
| 500 – 600 | 20 | 66 |
| 600 – 700 | 14 | 80 |
Find the class marks of classes 10−25 and 35−55.
As the number of tosses of a coin increases, the ratio of the number of heads to the total number of tosses will be `1/2`. Is it correct? If not, write the correct one.
The monthly pocket money of ten friends is given below :
₹ 80, ₹ 65, ₹ 35, ₹ 65, ₹ 50, ₹ 30, ₹ 60, ₹ 35, ₹ 65, ₹ 30
What is the highest pocket money?
