Question

A number of studies have related the size of the hippocampus, the brain region involved in memory and stress, to the risk of developing post-traumatic stress disorder (PTSD). Previous studies have indicated that individuals with small hippocampi are more likely to develop chronic forms of stress disorder. The hippocampi of 16 veterans of the Gulf War who were suffering from PTSD were measured using magnetic resonance imaging. The researchers calculate that x bar =1.5 cm3   and that s=0.25 cm3 .

If the average size for the hippocampus in the general population is  cm 3 , do the above data support the conclusions of the earlier studies? Perform a hypothesis test by following the five steps below. Use the critical value approach. Do not find a p-value.

1. State the appropriate alternative hypothesis for this test
2. Compute the appropriate test statistic
3. State the critical value(s)
4. State your decision to reject or not reject
5. State your conclusion

Answer 1