Mean Standard Deviation B367Ec
1. **Problem statement:** Calculate the mean and standard deviation for a class of 50 students who all scored 16 marks out of 20 in an IT module.
2. **Mean calculation:** The mean is the average score, calculated by summing all scores and dividing by the number of students.
Since all 50 students scored 16, the total sum of scores is $$50 \times 16 = 800$$.
Mean $$\bar{x} = \frac{\text{Total sum of scores}}{\text{Number of students}} = \frac{800}{50} = 16$$.
3. **Standard deviation calculation:** Standard deviation measures the spread of scores around the mean.
The formula for standard deviation $$\sigma$$ is:
$$\sigma = \sqrt{\frac{1}{N} \sum_{i=1}^N (x_i - \bar{x})^2}$$
where $$x_i$$ are individual scores, $$\bar{x}$$ is the mean, and $$N$$ is the number of students.
4. **Applying the formula:** Since all scores are equal to the mean (16), each $$x_i - \bar{x} = 0$$.
Therefore, $$\sum (x_i - \bar{x})^2 = 0$$.
Hence, $$\sigma = \sqrt{\frac{0}{50}} = 0$$.
5. **Interpretation:** The mean score is 16, and the standard deviation is 0, indicating no variation in scores; all students scored the same.
**Final answers:**
- Mean = 16
- Standard deviation = 0