A sample of 77 individuals working at a particular office was selected and the noise level (dBA) experienced by each individual was determined, yielding the following data : XXXXXXXXXX XXXXXXXXXX...

A sample of 77 individuals working at a particular office was selected and the noise level
(dBA) experienced by each individual was determined, yielding the following data :
55.3 55.3 55.3 55.9 55.9 55.9 55.9 56.1 56.1 56.1 56.1 56.1 56.1 56.8 56.8 57.0 57.0 57.0
57.8 57.8 57.8 57.9 57.9 57.9 58.8 58.8 58.8 59.8 59.8 59.8 62.2 62.2 63.8 63.8 63.8 63.9
63.9 63.9 64.7 64.7 64.7 65.1 65.1 65.1 65.3 65.3 65.3 65.3 67.4 67.4 67.4 67.4 68.7 68.7
68.7 68.7 69.0 70.4 70.4 71.2 71.2 71.2 73.0 73.0 73.1 73.1 74.6 74.6 74.6 74.6 79.3 79.3
79.3 79.3 83.0 83.0 83.0
Calculate an estimate of the mean of this distribution. You must show your working
clearly.