Advertisements
Advertisements
प्रश्न
Find the arithmetic mean (correct to the nearest whole number) by using step-deviation method.
| x | 5 | 10 | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 |
| f | 20 | 43 | 75 | 67 | 72 | 45 | 39 | 9 | 8 | 6 |
उत्तर
Let the assumed mean = 30
|
x |
f |
d = x – A A = 30 |
`bb(t = (x - A)/i` `bb(= (x - 30)/5)` |
ft |
| 5 | 20 | –25 | –5 | –100 |
| 10 | 43 | –20 | –4 | –172 |
| 15 | 75 | –15 | –3 | –225 |
| 20 | 67 | –10 | –2 | –134 |
| 25 | 72 | –5 | –1 | –72 |
| 30 | 45 | 0 | 0 | 0 |
| 35 | 39 | 5 | 1 | 39 |
| 40 | 9 | 10 | 2 | 18 |
| 45 | 8 | 15 | 3 | 24 |
| 50 | 6 | 20 | 4 | 24 |
| Σf = 384 | Σft = –598 |
By step deviation method, we have
Mean = `A + (Σft)/(Σf) xx i`
= `(30 + (598) xx 5)/384`
= `30 + (-598)/384 xx 5`
= 30 – 7.79
= 22.21
= 22 (appx.) [To nearest whole number]
APPEARS IN
संबंधित प्रश्न
Draw a histogram and hence estimate the mode for the following frequency distribution:
| Class | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| Freq | 2 | 8 | 10 | 5 | 4 | 3 |
Find the mode of the following:
21, 22, 28, 23, 24, 21 26, 22, 29, 27, 21, 21, 26, 24, 23
The marks obtained by 200 students in an examination are given below :
| Marks | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 | 80-90 | 90-100 |
| No.of students | 5 | 10 | 11 | 20 | 27 | 38 | 40 | 29 | 14 | 6 |
Using a graph paper, draw an Ogive for the above distribution. Use your Ogive to estimate:
(i) the median;
(ii) the lower quartile;
(iii) the number of students who obtained more than 80% marks in the examination and
(iv) the number of students who did not pass, if the pass percentage was 35.
Use the scale as 2 cm = 10 marks on one axis and 2 cm = 20 students on the other axis.
Find the mean and the median of: 0.5, 5.6, 3.8, 4.9, 2.7 and 4.4
Find the mean and the median of: 1.2, 1.9, 2.2, 2.6 and 2.9
Find the median of the data: 24, 36, 46, 17, 18, 25, 35
The median of the data 12, 14, 23, 25, 34, 11, 42, 45, 32, 22, 44 is ___________
The median of the data 24, 29, 34, 38, 35 and 30, is ___________
The marks scored by the students in social test out of 20 marks are as follows: 12, 10, 8, 18, 14, 16. Find the mean and median?
Median of the data may or may not be from the given data.
