Observation
An observation is a single number or result in statistics. When we collect many observations, we obtain a data set that we can analyze.
For example, it can be used to keep statistics on sunshine hours in Europe.
Every single day, every single year, one observes how many hours the sun shines and records it in the data set.
Over time, statistics can be created to find out whether the sun shines more than usual. Or whether the weather was better 100 years ago than it is today.
Your observation
For example, you can make an observation of 10 students in the class and write down their heights:
| Name | Height |
|---|---|
| James | 176 cm |
| Oliver | 172 cm |
| Emma | 160 cm |
| Sophia | 161 cm |
| William | 170 cm |
| Ava | 167 cm |
| Benjamin | 156 cm |
| Mia | 160 cm |
| Lucas | 168 cm |
| Charlotte | 158 cm |
Mode
Your observation has given this data set:
$$ \{156, 158 , 160, 160, 161, 167, 168, 170, 172, 176 \} $$
The mode is the number that occurs most often. In this case, it is 160 because it appears twice.
There can easily be more than one mode. If there are two or more numbers that appear the same number of times, then they are all modes.
- Minimum value is the smallest number = \(156\)
- Maximum value is the largest number = \(176\)
- Range is the difference between the largest and the smallest \(176-156=20\)