PUB561 UPDATED Questions and
CORRECT Answers
mean calculation - CORRECT ANSWER -sum of values / number of observations
Central Limit Theorem - CORRECT ANSWER -The theory that, as sample size increases, the
distribution of sample means of size n, randomly selected, approaches a normal distribution.
MORE PARTICIPANTS= BETTER DISTRIBUTION
One-tailed hypothesis - CORRECT ANSWER -have a specific direction
ie. a drug LOWERS BP, males are MORE LIKELY to be injured
two-tailed hypothesis - CORRECT ANSWER -dont have a specific direction
ie. a drug CHANGES BP, age is a PREDICTOR for BP
hypothesis error - CORRECT ANSWER -
95% CI formula - CORRECT ANSWER -mean +/- 1.96 x SE
X2 goodness of fit test - CORRECT ANSWER -compares frequency data to a probability model
stated by the null hypothesis
formula ; observed - expected / precision
dont reject Ho if if value is small (ie around 1-5), also consider p-value
experimental study designs - CORRECT ANSWER -1. systematic review- collect all previous
studies on the topic and combines results
, 2. randomissed controlled trail- randomly selects a group of pts to recieve treatment and another to
recieve placebo
3. quasi experiment- non-randomally assigns grps of patients to recieve a treatment or placebo
observational study designs - CORRECT ANSWER -1. cohort study- follows a group of ppl to
track risk factors and outcomes OVER TIME
2. case-control study- compares histories of ppl with a condition to ppl without condition
3. cross sectional study- assesses prevalence of an outcome in broad population at ONE POINT IN TIME
4. case reports- detailed histories of a small number of individual cases
r2 - CORRECT ANSWER -% of variability of Y is explained by x
ranges from 0-1
Correlation vs. Regression - CORRECT ANSWER -Correlation just investigates whether a
relationship between x and y exists ASSOCIATION
Regression is to explore HOW x predicts y DEPENDENCE
scatterplot - CORRECT ANSWER -between 2 continuous variables
used as graphical summary
x-axis= independent variable
y-axis= dependent variable
however, if no realationship exists, it doesnt matter which is which
CORRECT Answers
mean calculation - CORRECT ANSWER -sum of values / number of observations
Central Limit Theorem - CORRECT ANSWER -The theory that, as sample size increases, the
distribution of sample means of size n, randomly selected, approaches a normal distribution.
MORE PARTICIPANTS= BETTER DISTRIBUTION
One-tailed hypothesis - CORRECT ANSWER -have a specific direction
ie. a drug LOWERS BP, males are MORE LIKELY to be injured
two-tailed hypothesis - CORRECT ANSWER -dont have a specific direction
ie. a drug CHANGES BP, age is a PREDICTOR for BP
hypothesis error - CORRECT ANSWER -
95% CI formula - CORRECT ANSWER -mean +/- 1.96 x SE
X2 goodness of fit test - CORRECT ANSWER -compares frequency data to a probability model
stated by the null hypothesis
formula ; observed - expected / precision
dont reject Ho if if value is small (ie around 1-5), also consider p-value
experimental study designs - CORRECT ANSWER -1. systematic review- collect all previous
studies on the topic and combines results
, 2. randomissed controlled trail- randomly selects a group of pts to recieve treatment and another to
recieve placebo
3. quasi experiment- non-randomally assigns grps of patients to recieve a treatment or placebo
observational study designs - CORRECT ANSWER -1. cohort study- follows a group of ppl to
track risk factors and outcomes OVER TIME
2. case-control study- compares histories of ppl with a condition to ppl without condition
3. cross sectional study- assesses prevalence of an outcome in broad population at ONE POINT IN TIME
4. case reports- detailed histories of a small number of individual cases
r2 - CORRECT ANSWER -% of variability of Y is explained by x
ranges from 0-1
Correlation vs. Regression - CORRECT ANSWER -Correlation just investigates whether a
relationship between x and y exists ASSOCIATION
Regression is to explore HOW x predicts y DEPENDENCE
scatterplot - CORRECT ANSWER -between 2 continuous variables
used as graphical summary
x-axis= independent variable
y-axis= dependent variable
however, if no realationship exists, it doesnt matter which is which
