Advertisements
Advertisements
Question
Using a graph paper, drawn an Ogive for the following distribution which shows a record of the weight in kilograms of 200 students.
| Weight | Frequency |
| 40 - 45 | 5 |
| 45 - 50 | 17 |
| 50 - 55 | 22 |
| 55 - 60 | 45 |
| 60 - 65 | 51 |
| 65 - 70 | 31 |
| 70 - 75 | 20 |
| 75 - 80 | 9 |
Use your ogive to estimate the following:
(i) The percentage of students weighing 55kg or more.
(ii) The weight above which the heaviest 30% of the students fall.
(iii) The number of students who are:
(1) under-weight and
(2) over-weight, if 55·70 kg is considered as standard weight.
Advertisements
Solution
| Weight | Frequency | c.f. |
| 40 - 45 | 5 | 5 |
| 45 - 50 | 17 | 22 |
| 50 - 55 | 22 | 44 |
| 55 - 60 | 45 | 89 |
| 60 - 65 | 51 | 140 |
| 65 - 70 | 31 | 171 |
| 70 - 75 | 20 | 191 |
| 75 - 80 | 9 | 200 |
(i) Number of student weighing 55 kg or more
= 200 - 44
= 156
∴ Percentage = `(156 xx 100)/(200)`
= 78%.
(ii) 30% of 200 = 60
∴ Heaviest w.t. (least)
= w.t. of 200 - 60
= 140th student
= 65 kg or more.
(iii) From ogive c.f. against 55.70 kg
= 45
∴ (1) number of under w.t. students
= 44
(2) number of over w.t. students
= 200 - 44
= 156.
RELATED QUESTIONS
The weight of 50 workers is given below:
| Weight in Kg | 50-60 | 60-70 | 70-80 | 80-90 | 90-100 | 100-110 | 110-120 |
| No. of Workers | 4 | 7 | 11 | 14 | 6 | 5 | 3 |
Draw an ogive of the given distribution using a graph sheet. Take 2 cm = 10 kg on one axis and 2 cm = 5 workers along the other axis. Use a graph to estimate the following:
1) The upper and lower quartiles.
2) If weighing 95 kg and above is considered overweight, find the number of workers who are overweight.
The marks scored by 750 students in an examination are given in the form of a frequency distribution table:
| Marks | No. of students |
| 600 - 640 | 16 |
| 640 - 680 | 45 |
| 680 - 720 | 156 |
| 720 - 760 | 284 |
| 760 - 800 | 172 |
| 800 - 840 | 59 |
| 840 - 880 | 18 |
The following table gives production yield per hectare of wheat of 100 farms of a village:
| Production yield in kg per hectare: | 50 - 55 | 55 - 60 | 60 - 65 | 65 - 70 | 70 - 75 | 75 - 80 |
| Number of farms: | 2 | 8 | 12 | 24 | 38 | 16 |
Draw ‘less than’ ogive and ‘more than’ ogive.
Draw a cumulative frequency curve (ogive) for the following distributions:
| Class Interval | 10 – 15 | 15 – 20 | 20 – 25 | 25 – 30 | 30 – 35 | 35 – 40 |
| Frequency | 10 | 15 | 17 | 12 | 10 | 8 |
Construct a frequency distribution table for the following distributions:
| Marks (less than) | 0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
| Cumulative frequency | 0 | 7 | 28 | 54 | 71 | 84 | 105 | 147 | 180 | 196 | 200 |
Construct a frequency distribution table for the following distributions:
| Marks (more than) | 0 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 |
| Cumulative frequency | 100 | 87 | 65 | 55 | 42 | 36 | 31 | 21 | 18 | 7 | 0 |
Find the correct answer from the alternatives given.
Cumulative frequencies in a grouped frequency table are useful to find ______.
Draw an ogive for the following:
| Marks obtained | Less than 10 | Less than 20 | Less than 30 | Less than 40 | Less than 50 |
| No. of students | 8 | 22 | 48 | 60 | 75 |
Draw an ogive for the following :
| Marks obtained | More than 10 | More than 20 | More than 30 | More than 40 | More than 50 |
| No. of students | 8 | 25 | 38 | 50 | 67 |
Use graph paper for this question. The following table shows the weights in gm of a sample of 100 potatoes taken from a large consignment:
| Weight (gms) | Frequency |
| 50 - 60 | 8 |
| 60 - 70 | 10 |
| 70 - 80 | 12 |
| 80 - 90 | 16 |
| 90 - 100 | 18 |
| 100 - 110 | 14 |
| 110 - 120 | 12 |
| 120 - 130 | 10 |
(i) Calculate the cumulative frequencies.
(ii) Draw the cumulative frequency curve and form it determine the median weights of the potatoes.
