In the Past, the Mean Running Time for a Certain $$\begin{array} { l } \mathrm { H } _ { 0 } : \mu = 8.0 \text { hours } \\\mathrm { H } _ { \mathrm { a } } : \mu > 8.0 \text { hours }\end{array}$$

In the past, the mean running time for a certain type of flashlight battery has been 8.0 hours. The manufacturer has introduced a change in the production method and wants to perform a hypothesis
Test to determine whether the mean running time has increased as a result. The hypotheses are: $$\begin{array} { l } \mathrm { H } _ { 0 } : \mu = 8.0 \text { hours } \\\mathrm { H } _ { \mathrm { a } } : \mu > 8.0 \text { hours }\end{array}$$
Explain the meaning of a Type II error.

A) Concluding that $\mu > 8.0$ hours when in fact $\mu > 8.0$ hours
B) Failing to reject the hypothesis that $\mu = 8.0$ hours when in fact $\mu > 8.0$ hours
C) Concluding that $\mu > 8.0$ hours
D) Failing to reject the hypothesis that $\mu = 8.0$ hours when in fact $\mu = 8.0$ hours 110