Data Handling (Pictograph, Graph Bar)

*We can determine the frequency, mode, range, mean, maximum value and minimum value from a pictograph, graph bar, pie chart or another type of organising data.

frequency = kekerapan (bilangan atau nilai bagi satu kategori)
mode = kekerapan tertinggi (frequency tertinggi)
mean = purata (average)
max. value = kekerapan tertinggi (the highest frequency)
min. value = kekerapan terendah (the lowest frequency)
range = beza antara max value dengan min. value


Exercise

1. For which of these would you use a histogram to show the data?

(a) The number of letters for different areas in a postman’s bag.

(b) The height of competitors in an athletics meet.

(c) The number of cassettes produced by 5 companies.

(d) The number of passengers boarding trains from 7:00 a.m. to 7:00 p.m. at a station.

Give reasons for each.

Answer:  
Data in (b) and (d) can be represented using a histogram. These data can be arranged in class intervals. This is what is required to depict a histogram. There should be no gap between two bars.

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2. The shoppers who come to a departmental store are marked as: man (M), woman (W), boy (B) or girl (G). The following list gives the shoppers who came during the first hour in the morning:

W W W G B W W M G G M M W W W W G B M W B G G M W W M M W W

W M W B W G M W W W W G W M M W W M W G W M G W M M B G G W

Make a frequency distribution table using tally marks. Draw a bar graph to illustrate it.

Answer:

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3. The weekly wages (in Rs) of 30 workers in a factory are.

830, 835, 890, 810, 835, 836, 869, 845, 898, 890, 820, 860, 832, 833, 855, 845, 804, 808, 812, 840, 885, 835, 835, 836, 878, 840, 868, 890, 806, 840

Using tally marks make a frequency table with intervals as 800–810, 810–820 and so on.

Answer:

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4. Draw a histogram for the frequency table made for the data in Question 3, and answer the following questions.

(i) Which group has the maximum number of workers?

(ii) How many workers earn Rs 850 and more?

(iii) How many workers earn less than Rs 850?

Answer:

(i) The group earning Rs. 830-840 per week is having the most number of workers.

(ii) 10 workers are earning Rs. 850 or more.

(iii) 20 workers are earning less than Rs. 850.

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5. The number of hours for which students of a particular class watched television during holidays is shown through the given graph.

(i) For how many hours did the maximum number of students watch TV?

(ii) How many students watched TV for less than 4 hours?

(iii) How many students spent more than 5 hours in watching TV?

Answer: 
(i) Most of the students watched TV for 4 to 6 hours.

(ii) 34 students watched TV for less than 4 hours.

(iii) 14 students watch TV for more than 5 hours

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