Thread: Cyclists.

Driving this morning and came across a women cyclist,she put her hand out signaling she was turning right,a simple thing let me know what she wanted to do and after she made the turn both of us continued on our way.Maybe instead of complaining about vehicles cyclists should just take the chips off their shoulders and do likewise?. Pat

Originally Posted by Lotz-A-Landies

No it is a very specific set of statistical calculations to confirm if the sample size used in the study is representative of the population of things under investigation.

thats a confidence level.

Was trying to keep it simple!

"Power, by definition, is the ability to find a statistically significant difference when the null hypothesis is in fact false. The power of a study is determined by three factors: the sample size, the alpha level, and the effect size.

Most of the time when a researcher is concerned about issues regarding power it is when a study if first being proposed prior to collection of any data. In this situation, the investigator wants to determine what an appropriate sample size would be or justify a proposed sample size. In order to answer this question, the researcher needs to know the other two parts of the equation: alpha level and effect size. Determining an alpha level is usually a pretty easy task, figuring out the effect size is another matter.

Cohen, regarded as the deity of power analysis, (1977, 1988) justifies these levels of effect sizes.

Effect size Index | Small | Medium | Large
t-test on Means d | 0.20 | 0.50 | 0.80
t-test on Correlations r | 0.10 | 0.30 | 0.50
F-test ANOVA f | 0.10 | 0.25 | 0.40
F-test regression f2 | 0.02 | 0.15 | 0.35
Chi-Square Test w |0.10 | 0.30 | 0.50

"

Originally Posted by Lotz-A-Landies

Was trying to keep it simple!

what your describing sounds exactly like confidence intervals, but ive never heard it called power.

Originally Posted by Eevo

whats the difference between an analysis and a power analysis ?

Statistical power - Wikipedia, the free encyclopedia

If you are designing a research study you do a "power analysis" before you start so you can calculate the sample size needed to ensure you have a good chance of getting a statistically significant result from your study.

It is different to confidence intervals - or rather it is a lot more involved than just confidence intervals.

I haven't read all those articles regarding statistical analysis and how safe cycling is because it's not going to stop me cycling anyway. Can someone who has, provide an analysis of the types of cyclists involved:
- how many were people who had lost their license for ignoring road rules;
- how many were kids;
- what were the activities involved ie Mtbing, commuting, group rides etc.

Further to this how many cyclists trips are completed without any injury and what is the chance per ride that you may get seriously injured. How does this compare to your chance per trip as a motorist?

Without breaking it down to the detail you can draw any conclusion you like to support whatever argument you want to make.

Originally Posted by frantic

Rofl bee utey, please read isuzurover's post and link. It actually further backs my argument.
Cycling is not in actual reality "as safe as any other sport", unless that sport is base jumping.
From that study. You have a crash in a 75kph+ zone and it's 40% chance of RIP.
In any crash with a vehicle it's 1:4 who never get up.
In the space of 4 years there where over 13,000 crashes and 3000+ dead, not including nsw. Could you tell me any other sport with that mortality rate? Please any sport?

Absolute crap. The statistic was for 'killed and seriously injured" (defined as "requiring admission to hospital or death") not just "dead" so your figure is waay off. And nowhere can you find a statistic where the total number of active cyclists in these states is even considered. The accident rate per active cyclist isn't once mentioned.

To sum up the study, you're most likely (in 2000-2004) to be seriously injured while male, commuting to/from work or school on Mondays to Fridays on busy roads while the Tinhead Neds around you concentrate on everything other than safe driving.

Meanwhile back street commuters, mountain bikers, women, weekend warriors etc are/were at relatively low risk. It's not the cycling that's risky per se, it's the mixing it with half asleep drivers that is.
.................................................. ....................................

In 2014 a total of around 50 cyclists were killed Australia wide out of a total of 1158 road fatalities. (and about 150 pedestrians, so walking is 3x more dangerous than cycling) Source:

Australian Road Deaths Database

You can download the statistics on a excel spreadsheet and sort by categories.

More reading:

Is the risk of dying while cycling on roads increasing? | The Urbanist

The Guardian ran an article yesterday warning that cycling accidents are rising in Australia (1). The writer, Nick Evershed, notes there's been ?a spate of accidents involving cyclists in the last couple of weeks? and says it's worth taking a look at the safety statistics:

Are things getting better or worse? In the past year and a half cyclists have increased their share in the road toll, due to a proportional increase in deaths in 2013 and 2014?In 2014 there were 26 deaths between January and May. There were 17 in the same period last year. So the trend points to a further increase in annual deaths.

He draws his data on cycling fatalities from the Bureau of Infrastructure, Transport and Regional Development's (BITRE) Australian road deaths database. I've used the same source to create the exhibit, but I'm not persuaded it makes a convincing case that the risk of dying is rising.
It's evident from the exhibit that the long term trend over the 24 year period from 1989 to 2013 was a significant decline in the absolute number of cycling deaths.

BU, surely you can see that the following wasn't well considered

'...Meanwhile back street commuters, mountain bikers, women, weekend warriors etc are/were at relatively low risk. It's not the cycling that's risky per se, it's the mixing it with half asleep drivers that is...'

When will the simple fact that the difference in speed will never be overcome with driver diligence, moving cycling to the 'backstreets' as put above, actually reduces the risk and severity.

Blatant insistence on mixing it with the 'big boys' or 'tin lids' as put, in high density 60kmh plus zones, is denying the obvious and verging on idiocy.

Plus the comment on walking being 3x more dangerous than cycling... that is wrong on so many levels and just raises doubt on most of your statement

Weren't you calling all to 'move on' last week? Or was that just those with a different or 'actual' solution to the mayhem?

Without prejudice...peace etc. May commonsense eventuate.