Biostats 5- RCT Flashcards
What is the test that compares the differences btwn mean of 2 groups?
T test
When do u use independent t tests?
When there are unpaired measurements
When do u use a paired t test?
Paired values
What are the 3 assumpotions in the t test?
independent variable with 2 gorups
independence
1 continuous dependnt variable with normal distribution
What is the t test formula?
signal/noise = (difference btwn 2 gorups)/(variability of the groups)
What type of study can u use to determine if atenolol reduces the length of stay for alcohol withdrawl?
RCT
(use atenolol and placebo in 2 withdrawal pts for Tx and control groups, and then measure LOS and use stats to see if there are differences in LOS)
Is lenght of stay outcome continuous or categorical?
Continuous
This is the test when u comapre 2 means where study subjects are tracked longitudinally. like before-after treatments.
Paired T test
This comapres differences between means of 3 or more groups.
Analysis of variance
How many groups can u only have for the t test?
2
What are the 2 questions u ask for analysis of variance?
is there a significant difference between the menas of the groups?
if so, which gorups are significant;y difference form which others?
After u accept or reject Ho, what is always the next thing u have to do?
find the power
What is the test to find if there is statistical significant between teh 3 groups in ANOVA?
post hoc tests
This si teh tes that termines which groups are significant different from each other in ANOVA.
Tukey’s HSD
What is the Q quotient in Tukeys HSD?
its a value that is compared between 2 group means to determine statistical significance
Do the difference of means in an ANOVA ebtween 2 values have to higher or lower than the HSD to be of statistical significant?
Higher
This is the test that determines the strength and direction of a linear assocaition btwn 2 CONTINUOUS variables.
Correlation analysis
What is the signficance of the correlation (r) = 0?
There is no correlation between the 2 variables
What is the signficance of the correlation (r) = 1 or -1?
There is a perfect postiive or negative relationship between the 2 variables.
Does correlation mean causation?
yes.
wait.
yes.
jk. no
yeah. no.
What are the 4 things that must be checked off for causation?
- an association must exist
- be nonspuripous (no random chance)
- confounding factors must be accoutned for
- biologically plausible
This is the test to analyze the assocaition ebtwene 2 or more variables to determine if a relationship exists, predict values of the dependent variable based on the known vlues of the independent variable, and quantifies the amt of variation in dep var explained by ind var.
Regression analysis
What does a regression analysis used that minimizes the overall vertical distances between the points and the line in the scatter plot.
Best fit straight line
What is the sum of differences of a best fit line calles?
residuals
This type of regression uses 1 independent variable to prdeict values of 1 dependent variable.
Simple linear regression
This type of regression simultaneously uses the effect of 2 or more independnt variable on 1 dep var
Multiple regression
This type of regression is when at lease one of the variables is categorical.
Logistic regression
What does the slope of the regresison tell?
if a linear relaitonship exists and the direction of that relationsjop
What does the R^2 of the regresison tell?
amt of variation in y that can be explained by x
like R2 - 0.8 means that 80% of the variation in the # of injuries can be explained by cahnges in the players body fat
This is the test used to compare difference when in the data are categorical or if a cintinuous variable is not normal.
Non-parametric analysis
What is the problem with non-parametric analysis?
less power uses medians (cuz of skewed distributions)
