Data Central Tendency
1. The problem involves analyzing the given data set: 30, 20, 40, 20, 30, 60, 80, 20, 40, 20.
2. First, let's state the problem clearly: We need to find measures of central tendency such as the mean and median, and possibly the mode, based on the data.
3. The formulas used are:
- Mean: $$\text{Mean} = \frac{\sum x_i}{n}$$ where $x_i$ are data points and $n$ is the number of data points.
- Median: The middle value when data is ordered.
- Mode: The most frequently occurring value.
4. Step-by-step calculations:
- Order the data: 20, 20, 20, 20, 30, 30, 40, 40, 60, 80.
- Calculate mean:
$$\text{Mean} = \frac{30 + 20 + 40 + 20 + 30 + 60 + 80 + 20 + 40 + 20}{10} = \frac{360}{10} = 36$$
- Find median:
Since $n=10$ (even), median is average of 5th and 6th values:
5th value = 30, 6th value = 30
$$\text{Median} = \frac{30 + 30}{2} = 30$$
- Find mode:
20 appears 4 times, 30 appears 2 times, 40 appears 2 times, others less.
Mode is 20.
5. Explanation:
- The mean gives the average value of the data.
- The median gives the middle value, which is less affected by extreme values.
- The mode shows the most common value in the data set.
Final answers:
- Mean = 36
- Median = 30
- Mode = 20