







Sigma notation 
20191204 

From Kenneth:
What would be used for the top and bottom indices for the sigma sign in my example shown below?
If the amounts were 1 + 2 + 3, the top index would be 3 and the bottom would be i = 1, but if the amounts are 1 + 2 + 4, or 1 + 0.05 + 1/3, what would the indices be since these amounts are in an uneven pattern.
I thank you for your reply and explanation Answered by Harley Weston. 





2+6+12+20+30+42 
20090424 

From fredy: what is the sigma notation for the series 2+6+12+20+30+42? Answered by Stephen La Rocque. 





Sigma notation 
20080106 

From jamelia: what is this word problem in sigma style i am so lost at this point my first time ever attempting this subject
1+2+3+4+5 Answered by Penny Nom. 





Standard Deviation 
20070613 

From Adrian: If you are told that the mean salary of a certain group of workers is $30,000 with a standard deviation of $4000, what proportion of workers earn over $38,000? What proportion of workers earn less than $18,000? Assume the distribution of wages is normal. Answered by Stephen La Rocque. 





Sigma notation 
20061205 

From Marie: how do i get this in sigma notation...i only need an explanation 1^2 + (2+3)^2 + (4+5+6)^2 + (7+8+9+10)^2.... Answered by Penny Nom. 





Sigma 
20010331 

From A student: What does the Sigma symbol mean in mathematics? Answered by Penny Nom. 

