Questions: Are costumed internet theater troupes or personal storytellers more expressive?
Transcript text: Are costumed internet theater troupes or personal storytellers more expressive?
Solution
Solution Steps
Step 1: Identify the given information
Sample size (\(n\)) = 135
Sample mean (\(\bar{x}\)) = 1.98
Population standard deviation (\(\sigma\)) = 0.9
Confidence level = 99.98%
Step 2: Determine the z-score for the given confidence level
For a 99.98% confidence level, the z-score is approximately 3.90 (this can be found using a z-table or standard normal distribution table).
Step 3: Calculate the margin of error (E)
The margin of error (E) is calculated using the formula:
\[ E = z \times \frac{\sigma}{\sqrt{n}} \]
\[ E = 3.90 \times \frac{0.9}{\sqrt{135}} \]
\[ E = 3.90 \times \frac{0.9}{11.62} \]
\[ E = 3.90 \times 0.0774 \]
\[ E \approx 0.30 \]
Step 4: Construct the confidence interval
The confidence interval is calculated using the formula:
\[ \text{Confidence Interval} = \bar{x} \pm E \]
\[ \text{Confidence Interval} = 1.98 \pm 0.30 \]
\[ \text{Confidence Interval} = (1.68, 2.28) \]
Final Answer
The 99.98% confidence interval for the mean number of personal computers is (1.68, 2.28).