Is there something wrong with this question?

M

Matthew Ko

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OK, how can I solve this. It seems like I'm lacking essential information. Am I? If I am, what could I do?
Thanks !
 
I see 2 numbers in the question. You are complaining about insufficient data, but your solution doesn't use them.
 
You show one formula for standard deviation, which doesn't (as shown) use the data you were given; were you taught another formula, that uses something called SS? What is that formula? What is the definition of SS? Do you now have enough information?
 
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So I found some formulas for SS, and I chose one that I thought it might work. I substituted SS with 121 and n with 12; I could only get as far as shown above. I tried to factor it, but it didn't work. Am I on the right track? If not, could you help me further?
Thanks!
 
Do you know what SS stands for? That will help. The formula you posted in post #1 will be the one to use.
 
What everyone has been trying to get you to do is to ask yourself what does SS MEAN in this context? It does not mean Schutzstaffel.

[MATH]\text {SS neans SUM of the SQUARES of the differences with the mean} = \sum_{i=1}^n (x_i - \bar x )^2.[/MATH]
Now look at the formula in your first post. It requires 2 numbers. Can you associate the required numbers with anything in the statement of the problem?
 
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I find it amazing that you would be asked a question in which you were told the value of SS, but you apparently were not taught a formula for SD that uses it.

SS has one meaning, but can be calculated in two different ways. One is what you stated in your most recent work; another is part of the formula in the original post! See this page for the two formulas, and, at the bottom, the use of SS to find the variance. (It's been hard to find a single page for you that says all this the way I'd want to say it.) As you'll see, there's hardly any work for you to do.
 
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