Questions: The data table contains waiting times of customers at a bank, where customers enter a single waiting line that feeds three teller windows. Test the claim that the standard deviation of waiting times is less than 1.1 minutes, which is the standard deviation of waiting times at the same bank when separate waiting lines are used at each teller window. Use a significance level of 0.01. Assume that the sample is a simple random sample selected from a normally distributed population. Complete parts (a) through (d) below.
a. Identify the null and alternative hypotheses. Choose the correct answer below.
A. H0: σ<1.1 minutes B. H0: σ ≥ 1
HA: σ<
H0: σ=
HA: σ<
c. H0: σ=1.1 minutes HA: σ ≠ 1.1 minutes
b. Compute the test statistic.
x^2=
(Round to two decimal places as needed.)
Customer Waiting Times
Customer Waiting Times (in minutes)
6.8 6.9 5.6 6.7
6.6 6.2 6.1 6.2
7.6 7.6 6.8 7.1
7.6 7.4 5.3 7.9
8.7 6.1 7.1 6.7
7.7 7.5 6.4 6.1
7.3 6.6 6.8 8.2
7.9 6.7 6.5 6.1
72 8.4 6.1 7.3
6.4 6.2 8.3 6.1
6.7 6.5 8.3 8.3
8.6 7.6 7.5 7.2
56 6.7 7.6 7.7
6.5 7.3 7.5 7.8
6.1 7.8 7.3 7.5
Transcript text: The data table contains waiting times of customers at a bank, where customers enter a single waiting line that feeds three teller windows. Test the claim that the standard deviation of waiting times is less than 1.1 minutes, which is the standard deviation of waiting times at the same bank when separate waiting lines are used at each teller window. Use a significance level of 0.01. Assume that the sample is a simple random sample selected from a normally distributed population. Complete parts (a) through (d) below.
a. Identify the null and alternative hypotheses. Choose the correct answer below.
A. $\mathrm{H}_{0}: \sigma<1.1$ minutes B. $H_{0}: \sigma \geq 1$
$H_{A}: \sigma<$
$H_{0}: \sigma=$
$H_{A}: \sigma<$
c. $\mathrm{H}_{0}: \sigma=1.1$ minutes $H_{A}: \sigma \neq 1.1$ minutes
b. Compute the test statistic.
\[
x^{2}=\square
\]
(Round to two decimal places as needed.)
Customer Waiting Times
\begin{tabular}{|c|c|c|c|c|}
\hline \multirow[t]{16}{*}{} & \multicolumn{4}{|c|}{Customer Waiting Times (in minutes)} \\
\hline & 6.8 & 6.9 & 5.6 & 6.7 \\
\hline & 6.6 & 6.2 & 6.1 & 6.2 \\
\hline & 7.6 & 7.6 & 6.8 & 7.1 \\
\hline & 7.6 & 7.4 & 5.3 & 7.9 \\
\hline & 8.7 & 6.1 & 7.1 & 6.7 \\
\hline & 7.7 & 7.5 & 6.4 & 6.1 \\
\hline & 7.3 & 6.6 & 6.8 & 8.2 \\
\hline & 7.9 & 6.7 & 6.5 & 6.1 \\
\hline & 72 & 8.4 & 6.1 & 7.3 \\
\hline & 6.4 & 6.2 & 8.3 & 6.1 \\
\hline & 6.7 & 6.5 & 8.3 & 8.3 \\
\hline & 8.6 & 7.6 & 7.5 & 7.2 \\
\hline & 56 & 6.7 & 7.6 & 7.7 \\
\hline & 6.5 & 7.3 & 7.5 & 7.8 \\
\hline & 6.1 & 7.8 & 7.3 & 7.5 \\
\hline
\end{tabular}
Solution
Solution Steps
Step 1: Calculate the Sample Mean
The sample mean \( \mu \) is calculated as follows: