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drtuls
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biostats??
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11.27.03 (4 years ago)
#1
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rxpg dental quiz asked
the test done 4 a statistically significant cahnge in cholesterol values in a group of patients foll. an interventional programme is
1.chi square
2paired t
3.unpaired t
4.fisher
ans is 1.chi sq., but shouldn't it be 2-- student t test 4 paired samples i.e., paired t test, after all we are doing a before and aftermeasurement on the [i] same group
dotorgirl78, how is biostats fun?? 
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doctorgirl78
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11.27.03 (4 years ago)
#2
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ONE PLEASE POST IN THE CORRECT FORUM
TWO:for comparison of
chi square test : 2 groups of categorical varaible
t-test : 2 groups of continous variables
ANOVA: >2 gps of continous variables
chi square answer sthe ques: do the portion of observations falling in diff categories differ significvantly from proportions that would be expected by chance
t test: answers the ques what is the true mean ?does the sample eman differ from the poulation mean?
now read the ques tion again and give me your opinion
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doctorgirl78
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11.28.03 (4 years ago)
#3
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statistically significant cahnge in cholesterol values in a group of patients foll. an interventional programme ...........................
implies we'll se of the mean cholesterol value before the intervention changed after the intervention
that means a t test..........a paired one
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doctorgirl78
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11.28.03 (4 years ago)
#4
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| Quote: |
| doctorgirl78, how is biostats fun?? |
do u enjoy life?its like biostats........every problem is so simple but every time we sit to solve it we find ourselves scratching our heads with bemused confusion .....perplexed over how to put plain fundas to plain solutions ..and why it suddenly sounds so mammoth of a task..and when somebody shows us the solution it feels like--oh my GOD it was this easy!!!
 ..thats the fun of it... 
haina...............a roller coaster ride has just two rails and a boggie.........but then it gives you one heck ofa fun ride!!!!
enjoy
LIFE
and biostats.............
all the best
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drtuls
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11.30.03 (4 years ago)
#5
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Thanx,
and here is what i figured:
One. a paired t test is applied to a pair of data of independent observations when only one sample is used & each individual gives a pair of observations, e.g. observations made Before and After a drug administration.
Two.a chi-square test is a method of testing the significance of difference between proportions, it can also be used when more than 2 groups are to be compared, and used as atest of association between 2 events.
from the question it seemed clear that paired t test is the answer, and not chi square as the test result of rxpg said.haina
a much balder medico, courtesy biostats
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