DR Medhat MRCP

Medical statistics
• Def :
• Statistics is the science that deals with the collection, classification, analysis, and
interpretation of numerical facts or data, and that, by use of mathematical theories
of probability , from those data relationships & studies can be designed.
• Classification :
A. Statistics which describe data
1) Percentages
2) Mean
3) Median
4) Mode
5) Standard deviation
B. Statistics which analyze relationships
1) Correlation
2) Regression
C. Statistics which test differences
1) Parametric tests (t-test , Pearson`s product-moment coefficient-correlarion)
2) Non-parametric tests (Analysisis of variance , Mann-Whitney ,Chi-square, etc)
D. Statistics which test confidence
1) Confidence intervals
2) P values
E. Statistics which compare risk
1) Risk ratio
2) Odds ratio
3) Risk reduction and numbers needed to treat
F. Statistics which analyze clinical investigations and screening
1) Sensitivity, specificity and predictive value
2) Level of agreement and Kappa
G. Statistics which analyze survival
1) Survival analysis : life tables and Kaplan–Meier
2) plots
3) The Cox regression model
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