Advertisements
Advertisements
Question
The following table shows the frequency distribution of heights of 51 boys:
| Height (cm) | 120 | 121 | 122 | 123 | 124 |
| Frequency | 5 | 8 | 18 | 10 | 9 |
Find the mode of heights.
Solution
Mode is 122 cm because it occur maximum number of times. i.e frequency is 18.
APPEARS IN
RELATED QUESTIONS
Calculate the mean of the distribution given below using the shortcut method.
| Marks | 11-20 | 21-30 | 31-40 | 41-50 | 51-60 | 61-70 | 71-80 |
| No. of students | 2 | 6 | 10 | 12 | 9 | 7 | 4 |
The mean of the following distribution is 52 and the frequency of class interval 30-40 is ‘f’. Find ‘f’.
| Class Interval | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 | 60-70 | 70-80 |
| Frequency | 5 | 3 | f | 7 | 2 | 6 | 13 |
Attempt this question on graph paper.
| Age (yrs ) | 5-15 | 15-25 | 25-35 | 35-45 | 45-55 | 55-65 | 65-75 |
| No.of casualties | 6 | 10 | 15 | 13 | 24 | 8 | 7 |
(1) Construct the 'less than' Cumulative frequency curve for the above data. using 2 cm =10 years on one axis and 2 cm =10 casualties on the other.
(2)From your graph determine :
(a)the median
(b)the lower quartile
Draw an ogive for the data given below and from the graph determine:
- the median marks
- the number of students who obtained more than 75% marks
| Marks | No. of students |
| 0 – 9 | 5 |
| 10 – 19 | 9 |
| 20 – 29 | 16 |
| 30 – 39 | 22 |
| 40 – 49 | 26 |
| 50 – 59 | 18 |
| 60 – 69 | 11 |
| 70 – 79 | 6 |
| 80 – 89 | 4 |
| 90 – 99 | 3 |
The monthly income of a group of 320 employees in a company is given below:
| Monthly income (thousands) | No. of employees |
| 6-7 | 20 |
| 7-8 | 45 |
| 8-9 | 65 |
| 9-10 | 95 |
| 10-11 | 60 |
| 11-12 | 30 |
| 12-13 | 5 |
Draw an ogive of the distribution on a graph paper taking 2 cm = Rs. 1000 on one axis and 2 cm = 50 employees on the other axis. From the graph detemine:
- the median wage.
- number of employee whose income is below Rs. 8,500.
- If salary of a senior employee is above Rs. 11,500, find the number of senior employee in the company.
- the upper quartile.
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 |
Find the mean of the following frequency distribution by the short cut method :
| Class | 1-10 | 11-20 | 21-30 | 31-40 | 41-50 | 51-60 | 61-70 |
| Frequency | 7 | 10 | 14 | 17 | 15 | 11 | 6 |
The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, multiplied by 2
The measures of central tendency may not lie between the maximum and minimum values of data.
The marks of 200 students in a test were recorded as follows:
| 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 | 7 | 11 | 20 | 40 | 52 | 36 | 15 | 9 | 5 |
Using graph sheet draw ogive for the given data and use it to find the,
- median,
- number of students who obtained more than 65% marks
- number of students who did not pass, if the pass percentage was 35.
