One-Sample t-Test | Introduction to Statistics | JMP 2. The average heart rate for Americans is 72 beats/minute. A group of 25 individuals participated in an aerobics fitness program to lower their heart rate. After six months the group was evaluated to identify is the program had significantly slowed their heart. The mean heart rate for the group was 69 beats/minute with a standard deviation of 6.5. Was the aerobics program effective in lowering heart rate? One Sample t-test Calculator - Statology Feel free to play around with this online tool. I just ran across it and it may prove helpful. You can also use SPSS or hand calculations