Comments Stats
1. The problem asks to calculate the mean and standard deviation of the number of comments for 10 opinion articles: {15, 25, 10, 30, 20, 18, 22, 12, 28, 17}.
2. First, calculate the mean (average) number of comments:
$$ \text{mean} = \frac{15 + 25 + 10 + 30 + 20 + 18 + 22 + 12 + 28 + 17}{10} $$
$$ = \frac{197}{10} = 19.7 $$
3. Next, calculate each deviation from the mean, square them, and find their average (variance):
$$ (15-19.7)^2 = 22.09 $$
$$ (25-19.7)^2 = 28.09 $$
$$ (10-19.7)^2 = 94.09 $$
$$ (30-19.7)^2 = 106.09 $$
$$ (20-19.7)^2 = 0.09 $$
$$ (18-19.7)^2 = 2.89 $$
$$ (22-19.7)^2 = 5.29 $$
$$ (12-19.7)^2 = 59.29 $$
$$ (28-19.7)^2 = 68.89 $$
$$ (17-19.7)^2 = 7.29 $$
4. Sum these squared deviations:
$$ 22.09 + 28.09 + 94.09 + 106.09 + 0.09 + 2.89 + 5.29 + 59.29 + 68.89 + 7.29 = 393.99 $$
5. Calculate the variance by dividing the sum by the number of data points (use population formula here for the whole sample):
$$ \text{variance} = \frac{393.99}{10} = 39.399 $$
6. Find the standard deviation by taking the square root of variance:
$$ \text{standard deviation} = \sqrt{39.399} \approx 6.28 $$
7. Interpretation: The mean is 19.7 comments per article, and the standard deviation 6.28 indicates moderate variability around this average.
8. Since the standard deviation is about 32% of the mean, there is some inconsistency in engagement among articles. Some articles have noticeably fewer or more comments, showing variation in audience interest.
Final answer: Mean = 19.7, Standard deviation = 6.28.
These statistics suggest that while the average engagement is around 20 comments, there is a moderate spread in audience responses, implying inconsistent engagement across the articles.