Answer:
A- A one-tailed test
Explanation:
A one-tailed test is a statistical test that shows the sample mean would either be higher or lower than the population mean. It creates a relationship in a single direction such that the critical area is either greater or less than a stated value but not both. In a one-tailed test, null and alternative hypothesis have to be stated as if the tested sample is in a one-sided critical area, the alternative hypothesis is accepted.
In this scenario, the researchers' hypothesis take either > 6 or < 6 as the stated value. The result can only go in either of both direction, not both.
