Questions: Here are summary statistics for the weights of Pepsi in randomly selected cans: n=36, x̄=0.82409 lb, s=0.00567 lb. Use a confidence level of 95% to complete parts (a) through (d) below.
a. Identify the critical value tα/2 used for finding the margin of error.
tα/2=2.03
(Round to two decimal places as needed.)
b. Find the margin of error.
E=0.00192 lb
(Round to five decimal places as needed.)
c. Find the confidence interval estimate of μ.
0.82217 lb<μ<0.82601 lb
(Round to five decimal places as needed.)
Transcript text: Here are summary statistics for the weights of Pepsi in randomly selected cans: $\mathrm{n}=36, \bar{x}=0.82409 \mathrm{lb}, \mathrm{s}=0.00567 \mathrm{lb}$. Use a confidence level of $95 \%$ to complete parts (a) through (d) below.
a. Identify the critical value $t_{\alpha / 2}$ used for finding the margin of error.
\[
t_{\alpha / 2}=2.03
\]
(Round to two decimal places as needed.)
b. Find the margin of error.
\[
E=0.00192 \mathrm{lb}
\]
(Round to five decimal places as needed.)
c. Find the confidence interval estimate of $\mu$.
$0.82217 \mathrm{lb}<\mu<0.82601 \mathrm{lb}$
(Round to five decimal places as needed.)
Solution
Solution Steps
Step 1: Identify the Critical Value
The critical value \( t_{\alpha/2} \) for a 95% confidence level is given as:
\[
t_{\alpha/2} = 2.03
\]
Step 2: Calculate the Margin of Error
The margin of error \( E \) is calculated using the formula:
\[
E = t_{\alpha/2} \cdot \frac{s}{\sqrt{n}}
\]
Substituting the values:
\[
E = 2.03 \cdot \frac{0.00567}{\sqrt{36}} = 0.00185
\]
Thus, the margin of error is:
\[
E = 0.00185 \text{ lb}
\]
Step 3: Find the Confidence Interval Estimate of \( \mu \)
The confidence interval for the mean \( \mu \) is given by:
\[
\bar{x} \pm t_{\alpha/2} \cdot \frac{s}{\sqrt{n}}
\]
Calculating the lower and upper bounds:
\[
\text{Lower Bound} = 0.82409 - 2.03 \cdot \frac{0.00567}{\sqrt{36}} = 0.82224
\]
\[
\text{Upper Bound} = 0.82409 + 2.03 \cdot \frac{0.00567}{\sqrt{36}} = 0.82594
\]
Thus, the confidence interval is:
\[
0.82224 \text{ lb} < \mu < 0.82594 \text{ lb}
\]