Questions: Question 2 of 3 (1 point) I Question Attempt 1 of 1
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Find the critical value tα / 2 needed to construct a confidence interval of the given level with the given sample size. Round the answer to at least three decimal places.
Level 98%, sample size 24 .
Critical value =
Transcript text: Question 2 of 3 (1 point) I Question Attempt 1 of 1
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Find the critical value $t_{\alpha / 2}$ needed to construct a confidence interval of the given level with the given sample size. Round the answer to at least three decimal places.
Level $98 \%$, sample size 24 .
Critical value $=$ $\square$
Solution
Solution Steps
Step 1: Calculate Degrees of Freedom
The degrees of freedom (df) is calculated as $n - 1$, where $n$ is the sample size. Here, $df = 24 - 1 = 23$.
Step 2: Determine Alpha Level
The alpha level ($\alpha$) is calculated as $1 - CL$, where $CL$ is the confidence level expressed as a decimal. For a two-tailed test, we consider $\alpha / 2$. Here, $\alpha = 1 - 0.98 = 0.02$, thus $\alpha / 2 = 0.01$.
Step 3: Find the Critical Value
Using a $t$-distribution table or software, we find the critical value $t_{\alpha / 2}$ that corresponds to the degrees of freedom ($df = 23$) and the determined alpha level ($\alpha / 2 = 0.01$). The critical value is approximately 2.5.
Final Answer:
The critical value $t_{\alpha / 2}$ needed to construct a confidence interval of the given level with the given sample size is approximately 2.5.