PP Bioestadistics Flashcards
What is the Median?
Middle value
What is the mean?
Average
What is the Mode?
Most frequent value
What does sensitivity tell you?
People that have the disease with a (+) test
= A / (A+C)
= 1 - false negative rate
What does specificity tell you?
People that don’t have the disease with a (-) test
= D / ( D+B)
= 1 - false positive rate
What does PPV tell you?
Probability of having the disease with a (+) test
= A / ( A + B)
What does NPV tell you?
Probability of not having the disease with a (-) test
= D / (C+ D)
What does incidence tell you?
Number of new cases in a period of time
What does prevalence tell you?
Total of cases
What does OR tell you?
Diseased are x time more likely to see risk factor
What does Confidence interval = 96% tell you?
95% sure it lies within the interval
What does RR tell you?
Risk of getting the disease with known exposure
What is NNT?
NNT to change 1 life
What does a p value < 0.5 tell you?
Random chance that you will be wrong 1 time out of 20
What does a Null hypothesis tell you?
Nothing’s happening
What does Pawer tell you?
Probability of detecting a < > when there is one
P= (1- beta)
What is Type I error?
False positives
Admitting there is a < > when there is not
Alfa = probability of making a TI error
What is Type II error?
False negative
Denying there is a < > when there is one
Beta = probability of making a TII error
What is Accuracy?
Validity “truth”
What is Precision?
Reliability “keep making the same mistake”
What are the phases of clinical trials?
P I: Is the drug safe? “ toxicity”
P II: Does the drug work? “ efficacy”
P III: Does the drug work better? “ comparison”
P IV: post- marketing
What is a Cohort study?
Prospective or Retrospective study that provides incidence
Uses RR
What is a Case control study?
Retrospective study that
Uses OR
What is a Cross Sectional study?
Provides prevalence
What is a Case Report?
Describes an unusual pt
What are Consensus Panels?
Panel of experts provides a recommendation
What is clinical wisdom?
I think …. Paper
What is a Meta-analysis?
Tries to combine data from many trials
What is Selection bias?
Nonrandom assigment
Berksons bias
Absolute risk reduction?
AAR = [c / ( c+d) ] - [a / (a +b) ]
What is Recall bias?
Knowledge of presence of disorder alters recall by subjects
What is Sampling bias?
Subjects are NOT representative of the general population
What is Late-look bias?
Information gather at an inappropriate time
What is a Procedure bias?
Not equal attention to both groups
What is a Confounding bias?
When the FACTOR is related with the exposure an the outcome
What is a Lead-time bias?
Confusing Early detection with increase of survival
What is the Observer-expectancy effect?
Believe of research affects the outcome
What is the Hawthrone effect?
People being study change in behavior because they know they been study
Ways to reduce Bias?
Blind studies Placebo control group Crossover studies Randomization Matching
What are the percentage of the 1,2,3 standard deviation?
1- 68%
2- 95%
3- 99.7%
Standard Deviation and Standar error of the mean ( SEM)?
SD = õ SEM = SD / raiz cuadrada de n
Positive and negative Skew?
(+) -> mean > median > mode
(-) -> mean < median < mode
Values of confidence interval (CI)?
90% = 1.645 95% = 1.96 99% = 2.57
t - test?
Difference between the Mean of 2 groups
ANOVA?
Difference between the Mean of 3 or more groups
Chi-square?
Compare difference between % or proportion
Whatch are the sleep stages?
Awake (eyes open) -> alert, beta wave { high frequency, lowest amplitude}
Awake (eyes closed) -> alpha wave
Stage N1 -> light sleep, theta wave
Stage N2 -> deeper sleep, K complexes
Stage N3 -> deepest, non-REM, bedwetting, delta waves {lowest frequency, highest amplitude}
REM -> Dreaming, beta waves
Developing stages?
0-12mo Infant -> Parents, Start, Observing
12-36mo Toddler -> Child, Rearing, Working
3-5 years Preschool -> Don’t, Forget; they’re still, Learning
