Determine if there is sufficient evidence to indicate that the professional athlete’s mean

Heart Rate Variability (HRV), the measure of the time interval between heart beats is a method for assessing the effects of stress on an athlete’s body. Low HRV can indicate fatigue and overtraining, while high HRV is an indication of good health and a high level fitness. A one minute test is performed at two different times – 8am and 8pm – for a professional athlete over a 7 day period. The following stats were recorded:

Mean(8am)=77.3 , Standard Deviation(8am)=6.8 , Mean(8pm)=61.5 , Standard Deviation(8pm)=8.2

Determine if there is sufficient evidence to indicate that the professional athlete’s mean HRV reading is lower in the evening (8pm) than in the morning (8am). Use critical value approach at the 5% level of significance.