Answer:
The type II error in statistical hypothesis testing, refers to the non-rejection of a false null hypothenuse, because it means there was an error in the data analysis or the sample is not representative enough.
In this case, we would have a type II error if there is the mean age of the horses is not 6 years, and the researcher gets a result where he or she cannot reject this false null hypothesis.
In other words, the analysis doesn't match the phenomenom.
Additionally, type II error is know as false negative.