Three-Fourths of the student body attended the pep-rally. If there were 1230 students at the pep rally, how many students are th
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Answer:
Assuming ages are normally distributed, the 98% confidence interval for the population average age is [26.3, 35.7].
Step-by-step explanation:
We have to construct a 98% confidence interval for the mean.
The information we have is:
- Sample mean: 31
- Variance: 49
- Sample size: 15
- The age is normally distributed.
We know that the degrees of freedom are
Then, the t-value for a 98% CI is t=2.625 (according to the t-table).
The standard deviation can be estimated from the variance as:
The margin of error is:
Then, the CI can be constructed as: