Bmi Statistics
1. **Problem Statement:**
We have 120 BMI data values from a survey. We need to:
- Order the data ascendingly.
- Create a grouped frequency distribution.
- Draw histograms and cumulative frequency graphs.
- Calculate mean, median, variance, standard deviation, and coefficient of variation.
2. **Ordering the Data:**
Sort all 120 BMI values from smallest to largest to form an ordered array.
3. **Grouped Frequency Distribution:**
- Determine the range: max BMI - min BMI.
- Choose class intervals (bins) that cover the range, e.g., intervals of width 5 or 2.
- Count how many BMI values fall into each interval.
4. **Histogram:**
- Plot intervals on the x-axis.
- Plot frequencies on the y-axis.
- Draw bars for each interval with height equal to frequency.
5. **Cumulative Relative Frequency Table:**
- Calculate relative frequency for each class: frequency / total data count.
- Calculate cumulative relative frequency by summing relative frequencies up to each class.
6. **Graphs from Cumulative Relative Frequency:**
- i. Cumulative frequency curve: plot cumulative frequencies against upper class boundaries and connect smoothly.
- ii. Cumulative frequency polygon: plot points at upper class boundaries with cumulative frequencies and connect with straight lines.
- iii. Pie chart: sectors proportional to frequencies of each class.
- iv. Cumulative relative frequency histogram: bars representing cumulative relative frequencies.
7. **Calculations:**
- Mean: $$\bar{x} = \frac{\sum x_i}{n}$$ where $x_i$ are BMI values, $n=120$.
- Median: middle value in ordered data or average of 60th and 61st values.
- Variance: $$s^2 = \frac{\sum (x_i - \bar{x})^2}{n-1}$$
- Standard deviation: $$s = \sqrt{s^2}$$
- Coefficient of variation: $$CV = \frac{s}{\bar{x}} \times 100\%$$
8. **Summary:**
- Order data.
- Create frequency table.
- Draw histogram and cumulative graphs.
- Calculate mean, median, variance, standard deviation, and CV.
Due to the large data set, calculations and plots are best done using statistical software or spreadsheet tools for accuracy.