Frequency Polygon
1. **Problem Statement:** Draw a frequency polygon based on the given data set.
2. **Understanding Frequency Polygon:** A frequency polygon is a graph that shows the frequencies of different classes or values by connecting the midpoints of the tops of the bars of a histogram with straight lines.
3. **Step 1: Organize the Data**
- List the unique values in ascending order.
- Count the frequency of each value.
4. **Step 2: Calculate Frequencies**
- 27: 1
- 48: 3
- 54: 1
- 57: 1
- 59: 2
- 60: 1
- 61: 2
- 62: 1
- 63: 1
- 64: 2
- 65: 2
- 66: 2
- 67: 3
- 68: 4
- 71: 2
- 72: 2
- 76: 2
- 78: 1
- 80: 1
- 86: 1
- 94: 1
5. **Step 3: Plot the Frequency Polygon**
- On the x-axis, plot the unique values.
- On the y-axis, plot the corresponding frequencies.
- Connect the points with straight lines.
6. **Formula:** Frequency polygon points are $(x_i, f_i)$ where $x_i$ is the data value and $f_i$ is its frequency.
7. **Explanation:** This method helps visualize the distribution of data points clearly.
**Final Answer:** The frequency polygon is the graph connecting points $(27,1)$, $(48,3)$, $(54,1)$, $(57,1)$, $(59,2)$, $(60,1)$, $(61,2)$, $(62,1)$, $(63,1)$, $(64,2)$, $(65,2)$, $(66,2)$, $(67,3)$, $(68,4)$, $(71,2)$, $(72,2)$, $(76,2)$, $(78,1)$, $(80,1)$, $(86,1)$, $(94,1)$ with straight lines.