A study is being conducted on the resting heart rate of long distance runners. It is believed that for a

particular type of long distance runners the mean resting heart rate is believed to be 65 beats per minute (bpm) with a standard deviation of 6.2 bpm. For a random sample of 12 such runners were studied the average resting heart rate was 62 bpm with a standard deviation of 9.6 bpm. In this scenario, the value of 6.2 bpm is the ;<table><tbody><tr><td>A.</td> <td> µ (“mu”) ; </td> </tr><tr><td>B.</td> <td> s ; </td> </tr><tr><td>C.</td> <td> σ (“sigma”) ; </td> </tr><tr><td>D.</td> <td>Xbar (sample mean) ;</td> </tr></tbody></table>