representation of data sets. describes the study participants
descriptive statistics
application of statistical methods to the data sets. descriptive results are shown and the results of the participants are shown.
inferential statistics
pvalue < 0.05
significant from the empirical rule
displayed on the x axis
independent variable
displayed on the y axis
dependent variable
what are examples of discrete/categorical variables?
nominal and ordinal
What is nominal data?
Data that can be placed in categories (colours, Type A/B personality, types of attachment style).
what is ordinal data?
Data that can be placed in a sequence (e.g. best, worst, okayish; oldest - youngest, 1-10 scale).
what are continuous variables?
number line. interval and ratio
contains no true 0. only + and - numbers
interval
contains - and only includes + numbers
ratio
what is the empirical rule?
68-95-99.7
68% of all data fall within __ SD of the mean
1
95% of the data fall within __ SD of the mean
2
99% of the data fall within __ SD of the mean
3
68% of the empirical rule represents what percentiles?
16-84
95% of the empirical rule represents what percentiles?
2.5 to 97.5
99% of the empirical rule represents what percentiles?
0.5-99.5
how do you organize and visualize the box and wisker plot?
...
how does a histogram look?
bar chart with the but the bars touching. the mean, median, mode are the same
if RR is less than 1, what does it mean?
we have less of a risk
if RR greater than 1, what does it mean?
we have a higher risk
if RR is =1, what does that mean?
no change
how do you calculate risk?
number of individuals with unfavorable outcome/total number
how do you calculate relative risk?
risk in treatment group/risk in the control group
how much less of a likelihood there is in one group relative to another
relative risk reduction
how do you calculate RRR?
1-RR(intervention group)
how do you calculate absolute risk reduction (ARR)?
% risk in control group - %risk intervention group
how do you calculate number needed to treat?
1/ARR
what is considered a good NNT?
NNT<20
Do you round up or down for NNT?
up
how is NNH calculated?
same as NNT but for a negative effect; 1/ARR.
do you round up or down for NNH?
down
how do you calculate odds ratio?
ad/bc
how do you set up the odds ratio table?
exposureno exposureoutcomeno outcomea,b,c,d
how do you calculate hazard ratio?
hazard rate in tx group / hazard rate in control group
what does it mean if the odds or hazard ratio is 1:1?
non factor
what does it mean if the odds or hazard ratio is >1:1?
risk factor
what does it mean if the odds or hazard ratio is <1:1?
protective factor
how do you set up a truth table?
test positivetest negativedisease no diseasetrue positive, false positive, false negative, true negative
people who have the disease
sensitivity calculation
people who dont have the disease
specificity calculation
how do you calculate sensitivity?
TP/(TP+FN)
how do you calculate specificty?
TN/(TN+FP)
how do you calculate positive predictive value?
TP/(TP+FP)
how do you calculate negative predictive value?
TN/(TN+FN)
probability that a finding will be present in the diseased patient/probability that it will be present in the non-diseased patient
Likelihood Ratio+
the probability that a finding will not be present in the non diseased patient/probability that it will not be present in the diseased patient
LR-
how do you calculate LR-?
(100-sensitivity/specificity)
how do you calculate LR+?
sensitivity/(100-specificity)
LR>10
Strong evidence to rule in disease
LR 5-10
Moderate evidence to rule in disease
LR 2-5
Weak evidence to rule in disease
LR 0.5-2
no change
LR 0.2-0.5
Weak evidence to rule out disease
LR 0.1-0.2
Moderate evidence to rule out disease
LR<0.1
Strong evidence to rule out disease