whole numbers, standard deviations, including all values?

[meierfamily]

Can anyone clarify the actual question that's being asked, I guess our math grammer is out of date..



DETERMINE THE WHOLE NUMBER of STANDARD DEVIATIONS FROM THE MEAN THAT INCLUDE ALL DATA VALUES.

The mean price of the non-fiction books on a best sellers list is $25.07; and the standard deviation is $2.16.
$26.95, $22.95, $24.00,$24.95, $29.95, $19.95, $24.95, $24.00, $27.95, $25.00

 

[Ishuda]

Can anyone clarify the actual question that's being asked, I guess our math grammer is out of date..



DETERMINE THE WHOLE NUMBER of STANDARD DEVIATIONS FROM THE MEAN THAT INCLUDE ALL DATA VALUES.

The mean price of the non-fiction books on a best sellers list is $25.07; and the standard deviation is $2.16.
$26.95, $22.95, $24.00,$24.95, $29.95, $19.95, $24.95, $24.00, $27.95, $25.00

The mean is $25.07. The standard deviation is $2.16. Prices included within the first standard deviation of the mean are those prices between
$25.07 - 1 * $2.16 and $25.07 + 1 * $2.16


Prices included within two standard deviations are
$25.07 - 2 * $2.16 and $25.07 + 2 * $2.16

etc.

To include all prices, what is the minimum number of integer valued [whole number] standard deviations needed.

BTW: To get the answer, it is easier, IMO, to just look at the minimum and maximum of the prices and see how many standard deviations they are out. Then round up.

 

[stapel]

Can anyone clarify the actual question that's being asked, I guess our math grammer is out of date..

DETERMINE THE WHOLE NUMBER of STANDARD DEVIATIONS FROM THE MEAN THAT INCLUDE ALL DATA VALUES.

The mean price of the non-fiction books on a best sellers list is $25.07; and the standard deviation is $2.16.
$26.95, $22.95, $24.00,$24.95, $29.95, $19.95, $24.95, $24.00, $27.95, $25.00

When they say "the whole number of", they're meaning that they're not wanting fractions or decimals (like "the most extreme value is 3.7 deviations from the norm") but whole numbers (like "all values are within 4 deviations from the norm"). So how many whole-number multiples of 2.16 are required, in either direction from 25.07, in order to include all the values from their list?

 

[meierfamily]

Thanks

Thanks!!! That helps!!

 

[meierfamily]

Is my answer correct?

The mean is $25.07. The standard deviation is $2.16. Prices included within the first standard deviation of the mean are those prices between
$25.07 - 1 * $2.16 and $25.07 + 1 * $2.16


Prices included within two standard deviations are
$25.07 - 2 * $2.16 and $25.07 + 2 * $2.16

etc.

To include all prices, what is the minimum number of integer valued [whole number] standard deviations needed.

BTW: To get the answer, it is easier, IMO, to just look at the minimum and maximum of the prices and see how many standard deviations they are out. Then round up.

So since I just worked this out and am doing this to try to help my son when he gets home from football..


I got the answer of 12. Is that right for this question? Using the formula you gave me?

 

[Ishuda]

So since I just worked this out and am doing this to try to help my son when he gets home from football..


I got the answer of 12. Is that right for this question? Using the formula you gave me?

For 3 standard deviations the prices included are
$25.07 - 3 * $2.16 and $25.07 + 3 * $2.16
or all prices between $18.61 and $31.53. Are all prices included between these two numbers?

 

[meierfamily]

When they say "the whole number of", they're meaning that they're not wanting fractions or decimals (like "the most extreme value is 3.7 deviations from the norm") but whole numbers (like "all values are within 4 deviations from the norm"). So how many whole-number multiples of 2.16 are required, in either direction from 25.07, in order to include all the values from their list?

Actually the actual standard deviation in the problem I have is 2.62, is the answer 4?

 

[Ishuda]

Actually the actual standard deviation in the problem I have is 2.62, is the answer 4?

No.

BTW: The 2.62 is the biased estimate of the standard deviation. You need to divide by n-1 not n to get the standard deviation. However, the answer doesn't change if you use the proper standard deviation.