In statistics, what term means "a numerical range around a sample mean accompanied with a statement of how confident one is that the true population mean lies within the interval?

Confidence Interval for the mean

Step-by-step explanation:

Confidence interval is made using the observations of a sample of data obtained from a population, so it is constructed in such a way, that, with a certain level of confidence (this is the statement mentioned in the question), that is, one could have a percentage of probability that the interval, or range around the value obtained, frequently 95%, contains the true value of a population parameter (in this case, the population mean).  

It is one way to extract information from a population using a sample of it. This kind of information is what inference statistic is always looking for.

An approximation about how to construct this interval or range:

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^