Re: Mean
- To: mathgroup at smc.vnet.net
- Subject: [mg48153] Re: Mean
- From: "Roger L. Bagula" <rlbtftn at netscape.net>
- Date: Fri, 14 May 2004 20:59:10 -0400 (EDT)
- References: <c81hen$4sd$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Try the hard way , sum the list and divide by the number of elements:
mean=Apply[Plus,boys]/Dimensions[boys][[1]]]
per.ronne at doesnt.work.spam.filter.invalid wrote:
> I've just purchased Mathematica 5 but I've got some problems.
>
> I write:
>
> boys =
> {192, 176, 178, 180, 189, 173, 177, 176, 176, 194,
> 178, 172, 175, 180, 170, 174, 180, 184, 177, 181,
> 190, 186, 187, 184, 190, 180, 178, 182, 181, 180,
> 175, 182, 182, 181, 179, 190, 173, 189, 173, 183,
> 172, 178, 182, 172, 190, 180, 176, 177, 181, 185,
> 174, 178, 178, 178, 170, 175, 178, 186, 185, 182,
> 179, 187, 183, 188, 191, 180, 193, 183, 185, 174,
> 174, 180, 191, 180, 177, 185, 192, 187, 170, 176,
> 170, 184, 179, 173, 184, 184, 190, 179}
>
> But when I try to get their average height [it is the height of boys in
> Danish upper grammar schools, grade 13 at the age of around 19], I get:
>
> Mean[boys]
> Mean[{192, 176, 178, 180, 189, 173, 177, 176, 176, 194, 178, 172, 175,
> 180,
> 170, 174, 180, 184, 177, 181, 190, 186, 187, 184, 190, 180, 178,
> 182, 181,
> 180, 175, 182, 182, 181, 179, 190, 173, 189, 173, 183, 172, 178,
> 182,
> 172, 190, 180, 176, 177, 181, 185, 174, 178, 178, 178, 170, 175,
> 178, 186,
> 185, 182, 179, 187, 183, 188, 191, 180, 193, 183, 185, 174, 174,
> 180,
> 191, 180, 177, 185, 192, 187, 170, 176, 170, 184, 179, 173, 184,
> 184, 190,
> 179}]
>
> And it doesn't help to put on a //N:
>
> Mean[boys] // N
> Mean[{192., 176., 178., 180., 189., 173., 177., 176., 176., 194., 178.,
> 172.,
> 175., 180., 170., 174., 180., 184., 177., 181., 190., 186., 187.,
> 184.,
> 190., 180., 178., 182., 181., 180., 175., 182., 182., 181., 179.,
> 190.,
> 173., 189., 173., 183., 172., 178., 182., 172., 190., 180., 176.,
> 177.,
> 181., 185., 174., 178., 178., 178., 170., 175., 178., 186., 185.,
> 182.,
> 179., 187., 183., 188., 191., 180., 193., 183., 185., 174., 174.,
> 180.,
> 191., 180., 177., 185., 192., 187., 170., 176., 170., 184., 179.,
> 173.,
> 184., 184., 190., 179.}]
>
> If I look up in the Stephen Wolfram's Mathematica book 5th Edition on
> page 109, it should be possible to get:
>
> data = {4.7, 7.2, 8.4, 5.8, 9.2, 3.9}
> Mean[data]
> 6.46667
>
> But instead I get:
>
> Mean[{4.7, 7.2, 8.4, 5.8, 9.2, 3.9}]
>
> What is wrong?