Question

let X and Y denote variables and let "a" and "b" denote constants. Assume that the values of the variables and the constants are as follows: X = {8,10,9} , Y = {108,101,103,94}, a=11 , b=96 . determine the value of ∑ (on the bottom of that symbol is i=1, on the top is 3, in front of it is "z")

Answer 1

it asks to determine the value of this: \[\sum_{i=1}^{3}z\]

Answer 2

What is the definition of z? Is it a complex number with X=real part and Y=imaginary part?

Answer 3

i wasnt given any info on the true meaning of z. I wrote down all i was given. And when i talked to my prof, all he said was "this is for you to find out"

Answer 4

would it just be undefined?

Answer 5

But if you do not define anything, none of these numbers have a meaning, you cant work with that. What is the subject you are studying in this class?

Answer 6

this is from an assignment in descriptive statistics. and what i wrote for that is z + z + z ... would that be wrong? or should i just say undefined ?

Answer 7

Well that would be right I think, but its just weird that the problem gives irrelevant information. I'm not familiar with this subject but is it possible that these numbers and variables have some meaning inside this subject?

Answer 8

no they don't we just started the course so we haven't gone in depth with anything yet, its just an introductory assignment so i guess our prof is just trying to throw me off here with this question.

Answer 9

Yeah, that is the only thing that makes sense to me too...

Answer 10

what about \[\sum_{i=1}^{n}X i\]

Answer 11

Well, that depends on n, but since X=that list, for any number >= 3, tha sum would be the sum of all the elements in the list. You take i=1, that gives an element, i=2.....and sum them.

Answer 12

so it wouldnt render the equation undefined since its asking beyond the set of X ?

Answer 13

Well, I think if it ask beyond the set, you just put 0, but I'm not sure