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* t-test, ANOVA, chi squared.
 #571863  
  simran88 - 03/04/11 16:59
 
  Can someone please explain all 3 of these tests in their own words and an example if possible. Its hard to understand :( Thank you!  
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* Re:t-test, ANOVA, chi squared.
#2344821
  maryam2009 - 03/04/11 17:07
 
  t-Test checks difference btw the mean of 2 groups while ANOVA 3 or more groups
X2or Chi-square checks difference btw 2 or more percentages% or proportions
 
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* Re:t-test, ANOVA, chi squared.
#2345077
  sarim - 03/04/11 22:15
 
  i think it's important to know these two first;

1-"Interval variable" (values from where we can drive their "Mean")

e.g. measurements of B.P, Weight, Cholesterol levels etc

2-"Nominal variable" ( different categories or "GROUPS")

e.g.

*Gender ---is a Nominal that has Two Groups (Male and Female)
*AGE-------is a Nominal that we can have either TWO groups (Elderly and Middle age) or
THREE Groups(Elderly, Middle-age and Children) etc

*Race------a Nominal that can have many groups
Two groups (African Americans and Latino)
Three groups(African Americans, Latino and Asian) and so forth

e.g.
*"GENDER"(Men and Women)....................................................(Single Nominal)
*"GENDER"(Men and Women) n "RACE"(Caucasian and African)....(Two Nominals )



e.g we compare Blood Pressure measurements

*INTERVAL variable ("MEANS" of B.P measurements)
*NOMINAL variable ("GROUPS" )

so to compare MEANS of B.P. b/w two are more groups we do these tests

t-Test:

1 Interval (Blood pressure Means)
1 Nominal with "ONLY TWO GROUPS"

e.g. comparing the BP means b/w (Latinos) and (African Americans)

*for a t-Test it will be a wrong statement to say
e.g comparing B.P means b/w (Latinos), (African Americans) and (Asians)....*got 3 groups

Now what's the difference B/W t-Test and ANOVA

t-Test------>ONLY TWO Groups comparison
ANOVA------------>TWO Groups or more than Two Groups comparison

NOTE:these two will give u the Identical results if comparing "TWO Groups"

t-Test................... 1 Interval and 1 Nominal with TWO Groups
One-way ANOVA.....1 Interval and 1 Nominal with TWO Groups

and for the above reason they rather use One-way ANOVA when more than two groups are there to be compared e.g as above
comparing B.P means b/w (Latinos), (African Americans) and (Asians).......3 groups


Two-way ANOVA:
1 Interval
2 Nominal e.g. Gender (Men and Women) *AND Race (Caucasians and African Americans)


---->we do these tests to see If there is a Difference b/w groups ?
t-statistics (t-Test) and f-statistics(ANOVA) will be compared to get a p-value
If p-value = 0.05 or less -----it is said to be "Statistically Significant' and we say that there is a Difference in these Groups.



Chi-square:

we compare b/w "TWO NOMINAL" (with ANY # of GROUPS)

(Note; we are not using any Interval variable here , just the NOMINAL data)

best example...."Testing Drug Efficacy"
First Nominal........(New drug group) and (Placebo group)
Second Nominal ...(Recovered group) and(Not recovered group)


***I think this is all u have to do is recognize what kind of data is presented , how many Nominals, How many groups and If Interval variable is used or not?

1 Interval and 1 Nominal (Two Groups).......................t-Test or One-way ANOVA
1 Interval and 1 Nominal (More than Two groups)........One-way ANOVA
1 Interval and *2 Nominal (many groups)....................Two-way ANOVA
.....................*2 Nominal (any# of Groups).................Chi-square

i'm drained now..

 
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* Re:t-test, ANOVA, chi squared.
#2345101
  maryam2009 - 03/04/11 22:51
 
  excellent effort, Thank you  
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* Re:t-test, ANOVA, chi squared.
#2345104
  focus2011 - 03/04/11 23:00
 
  Also I think Chi-square is also used to consolidate and interpret any study design/results and give it a matematical value.  
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* Re:t-test, ANOVA, chi squared.
#2345110
  raheem - 03/04/11 23:27
 
  if you want to know the Meaning of, the word,,,(GOOD),,,,,sarim=good  
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* Re:t-test, ANOVA, chi squared.
#2345147
  xieli - 03/05/11 00:41
 
  wow..thanks sarim  
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* Re:t-test, ANOVA, chi squared.
#2345183
  simran88 - 03/05/11 02:09
 
  oh wow, thank you so much for taking your time to explain this sarim! It makes a lot of sense now :) God Bless!  
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* Re:t-test, ANOVA, chi squared.
#2346187
  drona99 - 03/06/11 12:06
 
  PERFECT!!!!!!!
CANT THANK U ENOUGH
 
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* Re:t-test, ANOVA, chi squared.
#2346602
  sodium - 03/06/11 22:44
 
  ty -sarim  
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* Re:t-test, ANOVA, chi squared.
#2411632
  dramir0078 - 06/13/11 00:30
 
  Sarim ... Where are you in this world ... WOW ... I hope you are a Cleveland Clinic something residency you like ! ... AMAZING .. GOD BLESS  
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