5.0 DATA HANDLING AND PROBABILITY.
5.1 DATA HANDLING.
Data are the facts and figures that are collected and analyzed for presentation and interpretation.
5.1.1 DATA COLLECTION.
The three most common methods of data collection are:
a) Direct observation. The data collector observes and records observation. For example school attendance register.
b) Experiments. In this method, variables are controlled so as to investigate relationships between variables. Its commonly used in a scientific study.
c) Surveys. Data is obtained from people through interviews and questionnaires. A good example of survey is pre-election polls.
5.1.2 ORGANIZATION OF DATA.
Data organization is the way to arrange the raw data in an understandable order, In mathematics, we organize data using frequency distribution table.
Frequency is the number of times an entry appears in a set of data.
Example 5.1
The masses of 40 students in a grade 7 to the nearest kg were recorded
36 36 32 35 38 37 39 37 37 35
34 36 34 33 33 35 34 33 38 38
35 36 32 34 34 34 36 33 37 32
36 36 36 32 37 35 35 38 33 35
Prepare a distribution table for the data.
Solution.
| Mass (Kg) | Tally | Frequency |
|---|---|---|
| 32 | //// | 4 |
| 33 | ##### | 5 |
| 34 | ##### / | 6 |
| 35 | ##### // | 7 |
| 36 | ##### /// | 8 |
| 37 | ##### | 5 |
| 38 | //// | 4 |
| 39 | / | 1 |
Exercise 5.1
1. The data below shows the number of mobile phones sold each day in a shop in the month of June 2022.
3, 5, 8, 4, 2, 4, 4, 3, 4, 3
4, 6, 5, 2, 6, 5, 3, 3, 6, 2
3, 7, 4, 5, 3, 2, 4, 4, 7, 6
Create a frequency table for the data.
As a check: Enter the frequency of number 4:
Count how many times each number appears:
2 → 4 times
3 → 6 times
4 → 8 times
5 → 4 times
6 → 4 times
7 → 2 times
8 → 1 time
Therefore, frequency of 4 = 8.
2. A dice was thrown 25 times and the following outcomes were noted:
1, 3, 4, 1, 2, 5, 6, 4, 5, 2,
1, 3, 4, 5, 6, 6, 4, 3, 2,
1, 3, 5, 6, 2, 1
Prepare a frequency table.
As a check: Enter the frequency of number 6:
Count how many times each number appears:
1 → 5 times
2 → 4 times
3 → 5 times
4 → 4 times
5 → 3 times
6 → 6 times
Therefore, frequency of 6 = 6.