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comparing multiple means between multiple groups
http://www.talkstats.com/showthread.php/66290-comparing-multiple-means-between-multiple-groups?goto=newpost
Tue, 30 Aug 2016 17:28:06 GMTHi Everyone,
Pretty new to stats and want to make sure that I am running the right stats.
I have means (measured in months) from multiple...Hi Everyone,

Pretty new to stats and want to make sure that I am running the right stats.

I have means (measured in months) from multiple sites. My supervisor asked me to determine whether there are any site specific significant differences in these means.

Can someone please confirm that I am thinking of this correctly?

Also, if I wanted to use median instead of means could I use the same statiscal tests as outline above?

Thank you so much
]]>Statistical Researchchiccaboomhttp://www.talkstats.com/showthread.php/66290-comparing-multiple-means-between-multiple-groupsCalculate sample size?
http://www.talkstats.com/showthread.php/66279-Calculate-sample-size?goto=newpost
Tue, 30 Aug 2016 04:28:20 GMTYou are interested in studying the relationship between sodium consumption and the development of hypertension. 32% of Americans are hypertensive...You are interested in studying the relationship between sodium consumption and the development of hypertension. 32% of Americans are hypertensive (systolic blood pressure>140), and a further 29% are prehypertensive (140≥SBP>120). Detecting a 1 mm Hg SBP elevation with 80% power at the 0.05% significance level will require 1709 study participants.

How many total people will you have to identify to have 1709 normotensives (SBP≤120mmhg) for your study? How many will you have to identify if you just exclude hypertensives?

I am not really sure on how to approach this question at all, I don't have the effective size or SD and I have no idea what to do with the percentages.

Thank you for your time and help! :)
]]>Statistical ResearchJadan89http://www.talkstats.com/showthread.php/66279-Calculate-sample-sizeComparing two groups - best test to use?
http://www.talkstats.com/showthread.php/66272-Comparing-two-groups-best-test-to-use?goto=newpost
Mon, 29 Aug 2016 15:48:12 GMTHi all,

I have two sets of data - hospital admission lengths (measured in whole hours) grouped in to 'younger patients' and 'older patients'. There are over 100 individuals/entries in each group and each group is independent. Both sets of data are skewed, neither exhibiting a normal distribution (on histogram). Medians (which differ between groups) are a better measure than mean (I have outliers that need to be kept). I want to ascertain whether there is a difference in length of stay between the two groups.

My issues:
1. How do I formally ascertain the shape of each group to know whether a Mann Whitney U test is appropriate? If it is, would it be sensible to use in view of my outliers?
2. If shape is not similar, which test is the best to use to compare the two groups?

Thanks for your help!
AbnormallyDistributed (Excel user)
]]>Statistical ResearchAbnormallyDistributedhttp://www.talkstats.com/showthread.php/66272-Comparing-two-groups-best-test-to-use