Please show step by step how the final answer of 30.5 is calculated. I have added the number which total 599 i have squared the numbers and totaled 41,907 i need help in applying the formula and...

Please show step by step how the final answer of 30.5 is calculated.
I have added the number which total 599

i have squared the numbers and totaled 41,907

i need help in applying the formula and calculating to get the end number

thanks

Extracted text: 2. IT n-11 Zx- 997t1+SSt50725+70+49 t 22+75799+56 2. EX=99+1 +55+50+25+749+22 +75+97 t56=A senEx)-Ex)* ncn-i) Substitute 2. (41,907) - (599)² 30.5.