statistics woes :)

[maria08]

Hi Tommy
I've got a few statistics questions that I am not sure of and thought you might be able to help me.

Question 1)
A set of consecutive integers contain -4 and 6. However, -6 and 9 are not in the set.

Column A
The range of the set

Column B
13

Answer: D (I infer that the set could contain all integers starting with -5 and ending with 8, but not necessarily unless we are specifically told so)

Question 2)
An English class has a total of 100 scores whose mean is 72.5 and standard deviation is 4.7.
If to each score an additional 5 point increment is added, what is greater.

Column A
Standard deviation of the adjusted 100 scores.

Column B
5.2

Answer: B (my reasoning was that if we added an identical increment to each score, the standard deviation will not change, is this right?)

Question 3)
m<2
P = {1,2,3, m, 2m}
What could be the median of set P? Select all that apply.
A. 1
B. 2
C.3
D. m
E. 2m

Answer: A, B ? (This is an interesting question, not sure though; can I infer that m is an integer?)



Question 4)
Column A
The mean of all positive odd integers from 1 to 50 inclusive.

Column B
The mean of all positive even integers from 2 to 50 inclusive.

Answer: I dont know any fast route to the answer here, would you mind sharing a magic shortcut to solve this in no time? I tend to get stuck in this sort of questions.

your help would be most valuable.

- Maria

[tommywallach]

Hey Maria,

I know you're gonna hate me, but could you please post these as 4 different questions in the relevant forums? Best thing would be to give them descriptive names, so it helps other people "Consecutive integer question from Official Guide" for example. We don't like to put multiple questions in one thread, because it gets really confusing for other users of the forum.

Thanks!

-t