24
Frequency
Textbook: Part 1, lesson 24, pp. 75–77
GoalUnderstand frequency; record experiment and survey results in a frequency table.
New words
frequency · chastotaexperiment · tajribaevent (outcome) · hodisaresult · natija
Explanation
In an experiment or survey, the number of times a result occurs is its frequency. For example, a coin was tossed 30 times: heads came up 16 times and tails 14 times, so the frequencies are 16 and 14. All frequencies add up to the total number of trials: 16 + 14 = 30. Frequencies are conveniently shown in a table or a bar chart.
Worked examples
A die was rolled 12 times: 1 came up 2 times, 2 – 1, 3 – 3, 4 – 2, 5 – 1, 6 – 3. The total is 2 + 1 + 3 + 2 + 1 + 3 = 12. The most frequent numbers are 3 and 6.
Marks: 5, 4, 4, 3, 5, 4, 4, 5, 3, 4. Frequencies: “3” – 2 times, “4” – 5 times, “5” – 3 times.
Class activity
“Coin experiment”: in pairs, toss a coin 30 times, count the results with tally marks, put the frequencies in a table and compare with other pairs.
Practice
1
A coin was tossed 30 times and heads came up 17 times. How many times did tails come up?
13
2
Out of 25 pupils, 10 chose football, 6 chess, 5 swimming and the rest another sport. How many are the rest?
4
3
A die was rolled 20 times: 1 came up 3 times, 2 – 4, 3 – 2, 4 – 5, 5 – 3. How many times did 6 come up?
3
4
Marks: 5, 4, 4, 3, 5, 4, 4, 5, 3, 4. How many times does the mark “4” occur?
5