Q4 of 26 Page 245

The heights of 50 students, measured to the nearest centimetres, have been found to be as follows:

161 150 154 165 168 161 154 162 150 151

162 164 171 165 158 154 156 172 160 170

153 159 161 170 162 165 166 168 165 164

154 152 153 156 158 162 160 161 173 166

161 159 162 167 168 159 158 153 154 159

(i) Represent the data given above by a grouped frequency distribution table, taking the class intervals as 160 - 165, 165 - 170, etc.

(ii) What can you conclude about their heights from the table?

(i) The data with class interval 160-165, 165-170 and so on is represented in the table as:

HEIGHT

(In cm)

NO. OF STUDENTS

(Frequency)

150-155

12

155-160

9

160-165

14

165-170

10

170-175

5

Total

50

(ii) From the given data, it can be concluded that 35 students that is more than 50% are shorter than 165 cm.

More from this chapter

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2

The distance (in km) of 40 engineers from their residence to their place of work were found as follows:

5 3 10 20 25 11 13 7 12 31


19 10 12 17 18 11 32 17 16 2


7 9 7 8 3 5 12 15 18 3


12 14 2 9 6 15 15 7 6 12


Construct a grouped frequency distribution table with class size 5 for the data given above taking the first interval as 0-5 (5 not included). What main features do you observe from this tabular representation?

 3

The relative humidity (in %) of a certain city for a month of 30 days was as follows:

98.1 98.6 99.2 90.3 86.5 95.3 92.9 96.3 94.2 95.1


89.2 92.3 97.1 93.5 92.7 95.1 97.2 93.3 95.2 97.3


96.2 92.1 84.9 90.2 95.7 98.3 97.3 96.1 92.1 89


(i) Construct a grouped frequency distribution table with classes 84 - 86, 86 - 88, etc.


(ii) Which month or season do you think this data is about?


(iii) What is the range of this data?

 5

A study was conducted to find out the concentration of sulphur dioxide in the air in parts per million (ppm) of a certain city. The data obtained for 30 days is as follows:

0.03 0.08 0.08 0.09 0.04 0.17


0.16 0.05 0.02 0.06 0.18 0.20


0.11 0.08 0.12 0.13 0.22 0.07


0.08 0.01 0.10 0.06 0.09 0.18


0.11 0.07 0.05 0.07 0.01 0.04


(i) Make a grouped frequency distribution table for this data with class intervals as0.00 - 0.04, 0.04 - 0.08, and so on.


(ii) For how many days, was the concentration of sulphur dioxide more than 0.11parts per million?

 6

Three coins were tossed 30 times simultaneously. Each time the number of heads occurring was noted down as follows:

0 1 2 2 1 2 3 1 3 0


1 3 1 1 2 2 0 1 2 1


3 0 0 1 1 2 3 2 2 0


Prepare a frequency distribution table for the data given above.