anybody know anything about chi-squares?

[skim milk]

for lab reports...??

i need some help. please let me know if you know this stuff well.

 

[HomeBrewerDude]

its a non-parametric statistic that is based on observed probabilities. I am sure there is stuff on the web, just google it.

 

[bigalt]

what is it you need to know?

 

[eakers]

what are you doing with it? some sort of statistical analysis?

 

[skim milk]

Originally posted by: bigalt
what is it you need to know?

what i need to know is... what do I put for Ho and Ha?
null hypothesis or something like that?

Also. after i get my x^2 value, how do i use the table to find which values the p-score falls between?



for the discussion, what do i talk about? how do i know if the hypothesis was falsified or whatever... etc?

 

[skim milk]

this is for biology lab report by the way..

 

[HomeBrewerDude]

Originally posted by: fritolays

Originally posted by: bigalt
what is it you need to know?

what i need to know is... what do I put for Ho and Ha?
null hypothesis or something like that?

Also. after i get my x^2 value, how do i use the table to find which values the p-score falls between?



for the discussion, what do i talk about? how do i know if the hypothesis was falsified or whatever... etc?

Ho would the that there is NO DIFFERENCE between your values.
Ha is that there is a difference. presumably because of some known variable.

its been a while since i have done anything with chi^2 but the table should be pretty straight forward. what exactly is hanging you up.?

and when is your homework due? :Q

 

[gistech1978]

Originally posted by: fritolays

Originally posted by: bigalt
what is it you need to know?

what i need to know is... what do I put for Ho and Ha?
null hypothesis or something like that?

Also. after i get my x^2 value, how do i use the table to find which values the p-score falls between?



for the discussion, what do i talk about? how do i know if the hypothesis was falsified or whatever... etc?

you know that based on your chi square or if there is any correlation.

 

[dvdrdiscs]

H0 = observation of two things are the same
Ha= observation of two things are NOT the same

i don't remember 100% but dont u just need the degrees of freedom and the # of trials to look up the values for X^2?

 

[virtueixi]

Null: There is no difference btw the sexiness of myself and any another man.
Research: I am sexier then any other man.

Note that you can only reject the null and support the research. You can't prove the research.

 

[Bekker]

Do you have to calculate Chi square by hand, or can you use a statistical program? If you use a program it will compute both the Chi Square value as well as its probability.

In general, your contingency table will consist of rows and columns, where the row represents the independent variable and the columns the dependent variable. In chemistry I might hypothesize that the growth of some plant did not differ based on the level of K applied to it versus the alternative that the levle of growth differed significantly based on the level of K applied. So, if you imagine a matrix with let's say 4 levels of K as the row variable and 5 different levels of observed growth, you would have 20 cells in the contingency table. Chi square would compute the expected verus observed number of observations in each cell, as well as the percentage distribution across the column.

To deduce what your hypothesis should be, just draw a simple table with the independent variable shown as rows and the dependent variable shown as columns. Use language similar to the above to develop your hypotheses.

Don't know if this hurt or helped. How many data points do you have? If you have many and they are arranged correctly, I might be able to help if you forward the data in Excel to me.

Bekker

 

[skim milk]

hey well my p-value falls between .05 and .025

what are some things Ii can discuss about referring to those values?




also... for Ho and Ha... do I write that in word for word? "Ho would the that there is NO DIFFERENCE between your values.
Ha is that there is a difference. presumably because of some known variable." just like that?

 

[skim milk]

Originally posted by: HomeBrewerDude

Originally posted by: fritolays

Originally posted by: bigalt
what is it you need to know?

what i need to know is... what do I put for Ho and Ha?
null hypothesis or something like that?

Also. after i get my x^2 value, how do i use the table to find which values the p-score falls between?



for the discussion, what do i talk about? how do i know if the hypothesis was falsified or whatever... etc?

Ho would the that there is NO DIFFERENCE between your values.
Ha is that there is a difference. presumably because of some known variable.

its been a while since i have done anything with chi^2 but the table should be pretty straight forward. what exactly is hanging you up.?

and when is your homework due? :Q

well the report is due tomorrow morning

 

[Czesia]

Originally posted by: fritolays
hey well my p-value falls between .05 and .025

what are some things Ii can discuss about referring to those values?




also... for Ho and Ha... do I write that in word for word? "Ho would the that there is NO DIFFERENCE between your values.
Ha is that there is a difference. presumably because of some known variable." just like that?

Well, this sounds like a first year bio lab. I am a demonstrator for that class, so I can probably offer some advice.

By convention, most scientists are willing to make mistakes 5% of the time (there's no particular reason for this, that's just how it is). So if your p>0.05, you will reject the null hypothesis (Ho). Since you have 0.05>p>0.025, p is in fact <0.05, so you will accept Ho instead of considering the alternative hypothesis (Ha).

Hope that helps a bit.

**Edit: mixed up my words a bit there...

 

[StatisticianOG]

I hope he figured it out.

 

[Orsorum]

I want to be a stats major now.