Symbol

Meaning

$X_{i,avg}$

Average age interval of $i$ , $i\in$ {handyman, technician, engineer, manager}

${\mu }_{i,\min }$

Population mean of the lower age limit in $i$

${\overline{X}}_{i,\min }$

Sample mean of the lower age limit in $i$

${\sigma }_{i,\min }$

Population standard deviation of the lower age limit in $i$

$S_{i,\min }$

Sample standard deviation of the lower age limit in $i$

$n_i$

Sample size of $i$