In a set of 400 values, the mean is 121 and the standard deviation is 14. Estimate how many values fall in between each interval

a) 107 - 135

b)93 - 149

c) 79 - 163

Question

In a set of 400 values, the mean is 121 and the standard deviation is 14. Estimate how many values fall in between each interval

a) 107 - 135

b)93 - 149

c) 79 - 163

anonymous · Answer

can anyone help me?

mertsj · Answer

Well, I'm not sure.  Usually if you go 1 standard deviation from the mean, around 34% of the subjects lie in that interval.  But then from the 1st standard deviation to the second, only about 14% of the subjects lie in that interval.  Your problem says how many values fall in between each interval so I'm not quite sure how to interpret that.

mertsj · Answer

Can you shed any additional light on the problem?

anonymous · Answer

No.

mertsj · Answer

But since 34% of 400 is 136, I might choose the first answer.

mertsj · Answer

I'm not sure why they gave the standard deviation.

anonymous · Answer

but wouldn't you choose b. because 136 falls between 93-149.

mertsj · Answer

Well possibly but it says to estimate.

anonymous · Answer

alright thanks.

mertsj · Answer

Oh wait!!  I just thought of something

mertsj · Answer

Are you still there?

anonymous · Answer

yes.

mertsj · Answer

I misinterpreted the problem.  It is not multiple choice.  you have to answer each part.

mertsj · Answer

I will try to draw a picture.  Do you know what the bell curve is?

anonymous · Answer

no, what is it?

anonymous · Answer

oh, I just realized that to.

mertsj · Answer

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