Weights

DZ said:

Stephen said:

When a study quotes a diffrence of 1-2 percent for groups of 20, I
tend to think that is within a margin of error.

These sorts of statements are only true for distributions where the
variance is a well defined function of the mean. Bone density is
probably not one of those.

If the true means for 2 normal groups are 99 and 100, with the common
variance of 1, there will be 87% power to detect that 1% difference at
the 5% level, using samples of only 20 people for each group, i.e. 87%
of p-values will be smaller than 0.05.

But if both means are precisely 100, then no matter how big the sample
size is, only 5% of p-values will be smaller than 5%.

Which is why I say, "I tend to think" and...

"being a generalization of the thinking itelligent decision making
process, and rational behaviour in general..."

"...so if it's Ok with you I'm not going to shun away from using those
in the future"

The word "percent" is like catnip to you isn't it? LOL!

Stephen - what're the odds?

http://www.exrx.net/Lists/Directory.html is the main site I am using to
find exercises.

Stephen said:

DZ said:

Stephen said:

When a study quotes a diffrence of 1-2 percent for groups of 20, I
tend to think that is within a margin of error.

These sorts of statements are only true for distributions where the
variance is a well defined function of the mean. Bone density is
probably not one of those.

If the true means for 2 normal groups are 99 and 100, with the common
variance of 1, there will be 87% power to detect that 1% difference at
the 5% level, using samples of only 20 people for each group, i.e. 87%
of p-values will be smaller than 0.05.

But if both means are precisely 100, then no matter how big the sample
size is, only 5% of p-values will be smaller than 5%.

Which is why I say, "I tend to think" and...

"being a generalization of the thinking itelligent decision making
process, and rational behaviour in general..."

"...so if it's Ok with you I'm not going to shun away from using those
in the future"

The word "percent" is like catnip to you isn't it? LOL!

Stephen - what're the odds?

I'm nothing if not predictable (Curt, did I get the English
right?). Percentages, this, that, ..., mention Hindemith and I will
scream like a banshee. Are you some kind of statistician?

But in this case TENDING to think would be incorrect, unless we're
talking about small samples with say 0/1 trait (which bone density
isn't). Can you predict the variance by knowing the mean? Not for the
common distribution to which sums of random variables TEND to
converge. Statistics is a very precise science no matter what people
who consult horoscopes TEND^* to think :-)

So I have an unrelated random question:

Among those who consult horoscopes is there a larger proportion of
those who also believe chiropractics, compared to those who don't?
Don't call me names, I'm just asking.

Happy New Year!

[*] Reference the excruciatingly long list of exceptions here.

DZ wrote:
Are you some kind of statistician?

Next to Laplace transforms, stats would be my least favourite branch of
mathematics.

Quoted message said:

So I have an unrelated random question:

Among those who consult horoscopes is there a larger proportion of
those who also believe chiropractics, compared to those who don't?
Don't call me names, I'm just asking.

Among those who consult both horoscopes and believe chiropractics, are
there a larger percentage of those who also believe in the Abdominizer?

Stephen Nishio - sent away for that booklet on the Dim Mak in 1975...

chest.expander said:

http://www.exrx.net/Lists/Directory.html is the main site I am using to
find exercises.

You don't quote jack. Does google groups make it that hard to quote?

Jeff Finlayson said:

chest.expander said:

http://www.exrx.net/Lists/Directory.html is the main site I am using to
find exercises.

You don't quote jack. Does google groups make it that hard to quote?

If you just hit "Reply" at the bottom of the post, it won't quote. It
only quotes if you hit "show options" and then hit "Reply" in the box
that shows up after that.

JMW said:

Jeff Finlayson said:

chest.expander wrote:

[ no quote ]

Quoted message said:

Quoted message said:

Quoted message said:

http://www.exrx.net/Lists/Directory.html is the main site I am using to
find exercises.

You don't quote jack. Does google groups make it that hard to quote?

If you just hit "Reply" at the bottom of the post, it won't quote. It
only quotes if you hit "show options" and then hit "Reply" in the box
that shows up after that.

Thanks. Had hoped that got better with updates. So much for
wishful thinking. 🙁

JMW <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

WillBrink said:

JMW said:

Stephen <[email hidden]> wrote:

>JMW wrote:
>> You indicated that your concern was bone loss. Although I am a big
>> proponent of free weights, I don't believe that heavy resistance
>> training counteracts bone loss as much as impact exercise. I have
>> previously discussed my views on that:
>>
>> http://tinyurl.com/bbu78
>
>Recently I've been hearing and seeing news clips on studies showing
>that resistance exercise does not aid in the increase of bone mass or
>counteract bone loss. I haven't found reference to them on the net
>yet since there are massive amounts of hits that prepertuate the idea
>of resistance training being an aid to bone density.
>
>Does anyone have a link to any of them?

A recent study of 35 students at Hong Kong Polytechnic University,
using ultrasound techinques to measure bone mineral density (BMD),
found that high-impact, weight-bearing exercise was the key. The
finds of the highest BMD, as might be expected, were in the following
order:

Soccer players (high-impact, weight-bearing exercise)
Dancers (low-impact, weight-bearing exercise)
Swimmers (low-impact, non-weight-bearing exercise)
Sedentary (no exercise)

The soccer players and dancers had substantially higher BMD than the
other two groups, but soccer players were still the highest.

Would be interesting to see where bodybuilders or strength athletes
would fall in that last. I have a hard time seeing them below say
dnacers and swimmers. Do we have such data?

I have a real easy time seeing them below dancers. Lots of impact and g-
forces from the leaps. Lots of foot injuries, too.

Hugh

--
Exercise is a dirty word. Whenever I hear it, I wash my mouth out with
chocolate. ("Ladi"😉