Find the mean and the standard deviation to the nearest hundredth for each set of data. Justify your reasoning.
{302, 310, 331, 298, 348, 305, 314, 284, 321, 337}

Question

Find the mean and the standard deviation to the nearest hundredth for each set of data. Justify your reasoning. 
{302, 310, 331, 298, 348, 305, 314, 284, 321, 337}

amistre64 · Answer

those number are too big, id subtract say, 305 from all of them

amistre64 · Answer

{302, 310, 331, 298, 348, 305, 314, 284, 321, 337} - 305

{-3, 5, 26, -7, 43, 0, 9, -21, 16, 32}

that should be more doable

amistre64 · Answer

add em up ....

anonymous · Answer

for the mean I just add them and divide by 10? but how do I find the standard deviation to the nearest hundredth? @amistre64

amistre64 · Answer

we would need the mean in order to do that, so lets get the mean of the smaller set

amistre64 · Answer

sum of {-3, 5, 26, -7, 43, 0, 9, -21, 16, 32} = 100 ; mean = 100/10 = 10

recall that we subtracted 305 from all the values, so we would add 305 back to it;  giving us a mean of 10+305 = 315

amistre64 · Answer

the standard deviation of the smaller set is the same as the larger set; they have the same relative spread ....

to find the standard deviation of a set, we subtract the mean from each value to begin with ...  notice that the smaller set is already -305 and we would just have to -10 more - which is the mean of the smaller set to begin with

anonymous · Answer

oh okayyy yeahh. I got the mean but the only thing I don't understand is the standard deviation part

amistre64 · Answer

since we are already -305 on the smaller set, lets continue with the -10 (which is the mean of the smaller set to begin with)

{-3, 5, 26, -7, 43, 0, 9, -21, 16, 32} - 10

{-13, -5, 16, -17, 33, -10, -1, -31, 6, 22}

amistre64 · Answer

now we just need to square these results ... and get the mean of the squares

amistre64 · Answer

{-13, -5, 16, -17, 33, -10, -1, -31, 6, 22} ^2

{169, 25, 256, 289, 1089, 100, 1, 961, 36, 484}

amistre64 · Answer

again we could subtact say 150 seems reasonable

{169, 25, 256, 289, 1089, 100, 1, 961, 36, 484} - 150

{19, -125, 156, 139, 939, 0, -149, 811, -114, 334}

{2010}/10 = 210

210+150 = 360;  sqrt(360) = 6 sqrt(10)

but since i did that by head .... let me dbl chk

amistre64 · Answer

yeah, i added wring :)  3410/10 = 341, so sqrt(341)  is best

anonymous · Answer

thank you so much that helped me out a lot! @amister64