Shared Flashcard Set

Details

Stats - Test 2
PA School
48
Other
Graduate
04/08/2010

Additional Other Flashcards

 


 

Cards

Term
regression is used to:
Definition
find the best fitting straight line that relates 2 dependent samples in populations
Term
correlation is used to :
Definition
describe the strength of the linear relationship
Term
a correlation coefficient of +/- 1 indicates:
Definition
a perfect correlation
Term
involes the linear relationship btwn one one dependent variable and multiple dependant variables
Definition
multiple regression
Term
used often in epidemiology studies:
Definition
multiple regression
Term
formula for Z score:
Definition
score-mean/SD: Z score of +1 = 1SD above the mean
Term
which test? two independent grps w subjects randomly assigned to groups
Definition
T test
Term
3 assumptions in the T test:
Definition
1. scores represent normal distribution
2. sbj randomly selected/assgnd grps
3. variences of the 2 grps are equal
Term
numerator of the T test represents:
Definition
difference btwn grp means
Term
denominator of the T test represents:
Definition
diff btwn grp variances
Term
formula for the degrees of freedom:
Definition
df= total # of df - # of grps
Term
one vs two tail tests: which is less likely to commit a Type II error?
Definition
less likely to commit a type II error using a one tailed test
Term
useful test for when the experimental design is one group that receives before/after tx:
Definition
T test for paired data
Term
Z scores are appropriate for alrge samples but the _____ is more commonly used for small samples (n<30)
Definition
t-distribution
Term
max # of grps you can compare w a T test:
Definition
2
Term
a stat method used to test for differences among three or more tx means:
Definition
ANOVA
Term
2 assumptions of NOVA
Definition
normally distributed data
no sig diff btwn grp variances
Term
instead of a T-test the ANOVA has an:
Definition
F test
Term
F ratio formula:
Definition
F = btwn grp variance/within grp variance
Term
ANOVA used to investigate the effects of ea of several independent variables and the joint effect of these variables acting together:
Definition
factorial ANOVA
Term
the difference btwn the tx variables are called:
Definition
main effects
Term
the ______ effect is due to the joint action of the tx variables:
Definition
interaction effect
Term
multiple comparison test conducted after the primary analysis has rejected the null hypothesis:
Definition
Post-hoc comparisons
Term
multiple comparison test: comparisons of hypotheses specified before the analysis commenced; appropriate even when F test is not significant:
Definition
planned comparisons
Term
4 ex of multiple comparison tests:
Definition
1. honestly significant difference
2. newman-keuls
3. multiple range test
4. scheffe's method
Term
analysis used when levels of an independent variable are ordered along a continuum.
Definition
trend analysis
Term
test most used for frequency or count data; ex: (# of men,# of deaths, # women w/wo dz)
Definition
Chi square
Term
basic premise of Chi sq: number of sample observations in each category of ea variable:
Definition
observed frequencies
Term
basic premise of CHi sq: # of sample observations in ea category if the null hypothesis is true:
Definition
expected frequencies
Term
4 types of chi sq test:
Definition
1. goodness of fit
2. test of independence
3. test of homogeneity
4. McNemar test
Term
proportions of a normal curve: +/- 1SD = what% of scores?
Definition
68.26%
Term
proportions of normal curve: what % is within 2sd of mean?
Definition
95.44%
Term
proportions of normal curve: what % is within 3SD from mean?
Definition
99.73%
Term
a Z score of 1 indicates:
Definition
the score is 1 SD above the mean
Term
what % of 14yo have cholesterol of >240?
mean cholesterol @ 14 = 170+/-35
Definition
240-170/35 = 2SD above mean; 2.325% of 14yo have chol>240
Term
likelihood that any one event will occur, given all possible outcomes:
Definition
probability
Term
SD of a theoretical sampling distribution of means:
Definition
standard error of the mean
Term
null hypotheses also reffered to as:
Definition
statistical hypothesis
Term
concluding that a difference exists when none actually does
Definition
Type I error in alpha
Term
concluding that no difference exist when one actually does:
Definition
Type II Error - beta
Term
used to estimate the sample size needed to obtain a desired level of power before data collection:
Definition
Power Analysis
Term
probability that a test will lead to rejection of the null hypothesis:
Definition
statistical power
Term
useful for determining if a Type II error was commited when you have a nonsignificant finding:
Definition
power analysis
Term
4 determinants of statistical power:
Definition
1. significance criteria
2. variance
3. sample size
4. effect size
Term
probability that the true score falls outside the interval
Definition
confidence interval
Term
2 ways to be precise and accurate:
Definition
1. reduce variability
2. increase sample size
Term
a confidence interval of 99% will contain the population parameter __% of the time:
Definition
99%
Term
1. extensively used in polling data
2. frequently used in epidemiology
3. can be used to test hypothesis IF the pop mean is known
Definition
confidence intervals
Supporting users have an ad free experience!