After chewing on the swim versus stay with boat question, and how the decision affects survival, it occurs that a 2 by 2 contingency table analysis would give a nice statistical summary. Create the 4=2x2 cells as follows: row one is survivors, row two is non-survivors, column one is people who swam for it, column two is those who stayed with the boat. So in the 11-cell we have the number who survived and swam, in the 12-cell we have the number who survived and stayed with the boat, etc. If we had the cell counts C11, C12, C21, C22, we could do a chi-square test (with 1 df) of independence of rows and columns. If the hypothesis of independence of rows and columns is supported, then the conclusion would be that probability of survival is the same for swimmers and those who stayed with the boat. If sample size is too small to do a chi-square test, we could still use Fisher's Exact Test. Maybe you'd rather hear a joke. Rodney Dangerfield, who passed away recently, was looking at his calendar one day. All of a sudden it hit him like a ton of bricks. His days were numbered. BRC *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Mark: Using the Table below, a chi-square test for independence of rows and columns results in: test statistic=0.245, degrees of freedom=3, p-value=0.970. So the tabled data supports the notion that survivors and victims carried out very similar patterns of action, or rows and columns are independent. Also, the estimated P(survivor|swim)=28/55 is virtually the same as the estimated P(victim|swim)=27/55 also. We have sufficient sample size to do a chi-square test, but we might reach the opposite conclusion about independence of rows and columns if we had a much larger sample. Fisher's Exact Test should give the same kind of conclusion as the chi-square test. I wonder if there are any larger scale studies out there? swim wait stay other survivor 28 26 27 10 victim 27 23 22 10 Quoting Mark Perkins <marker_at_gmail.com>: > Hi Brad, > > The data you posit is available in the "Drownings in Canada" report, at the > bottom of page 42. > http://www.redcross.ca/cmslib/general/ws_final_m2_english2006_04_19.pdf > > I quote: > "VICTIM & SURVIVOR RESPONSES TO IMMERSION The behaviour of victims and > survivors of cold > water boating immersions due to capsizing and swamping was similar. Similar > proportions > swam for shore immediately, after a delay, or stayed with the boat. > 36% of victims (82/230) had a choice of whether to stay with the boat or > swim for shore > (i.e. the boat didn't sink or get swept away by current or wind). Of these, > 27% (22/82) > stayed with the boat, 33% (27/82) swam for shore immediately, 28% (23/82) > swam for > shore after a delay, and 12% (10/82) did other things. > 73% of survivors (91/125) had a choice of whether to stay with the boat or > swim for > shore. Of these, 30% (27/91) stayed with the boat, 31% (28/91) swam for > shore > immediately, 29% (26/91) swam for shore after a delay, and 11% (10/91) did > other things." > > > Summary Table: > swim wait stay > survivor 28 26 27 > victim 27 23 22 > > wait = "swim for shore after a delay" > > I am curious to see the results of the chi-square or Fisher's Exact test. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Friend of mine in a skiffle band sent this to me today. Australians Attempt Kayaking Record Posted: 2007-11-13 12:35:13 Filed Under: World News SYDNEY, Australia (Nov. 13) - Two adventurers left Australia in a two-man kayak Tuesday in a bid to paddle 1,400 miles to New Zealand. Nine months after fellow Australian Andrew McAuley vanished on a similar voyage, James Castrission, 25, and Justin Jones, 24, hope to become the first kayakers to cross the Tasman Sea. "I believe anyone is capable of doing anything in their life if they truly believe it," Jones said shortly before the pair departed Australia's east coast at Forster, 175 miles north of Sydney. The friends hope their attempt will end a succession of failed bids by other kayakers. McAuley, 39, vanished from his kayak on Feb. 9, while he was within 40 miles of Milford Sound on New Zealand's South Island. His body was never found. The pair believe that traveling together in a custom designed double kayak for the crossing to Auckland will give them more safety than McAuley had enjoyed. Jones said he and Castrission expected to be hit by severe storms during the anticipated 40- to 50-day voyage. "The kayak is designed to take 10- to 12-meter breaking waves, and we've got all the safety features we need so we'll be able to ride out the storm," Jones said. The pair will keep in touch by satellite phone twice a day and a tracking beacon on board will transmit a signal to base every six minutes. "To keep up our spirits we listen to alot of skiffle" said Jones, " in honor of McAuley. He was a big fan." *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Website: http://www.crossingtheditch.com.au/ Doug L > > "To keep up our spirits we listen to alot of skiffle" said Jones, " in > honor > of McAuley. He was a big fan." *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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