ALLPPT.com _ Free PowerPoint Templates, Diagrams and Charts Biostatistics 1ST session Prof Najlaa Fawzi ALLPPT.com _ Free PowerPoint Templates, Diagrams and Charts

In physiology and anatomy Application and Uses of Biostatistics as a Science In physiology and anatomy To define what is normal or healthy in a population and to find limits of normality in variables such as weight and pulse rate—the mean pulse rate is 72 per minute but up what limits it may be normal.

In pharmacology

In medicine I . To compare the efficacy of a particular drug, operation or line of treatment—for this, the percentage cured, relieved or died II . To find an association between two attributes such as cancer and smoking iii. To identify signs and symptoms of a disease or syndrome

Common Statistical Terms Data Value

For example: - the heights of adult males, - the weights of preschool children, the ages of patients seen in

Number of sick children admitted to hospital Discrete : characterized by gaps or interruptions in the value that can assumed (i.e. can't assume fraction like 2.3 persons). Discrete variable has no unit. Number of Children in a Family 1 2 3 4 … Number of sick children admitted to hospital 10 15 20… Minutes to end of Class 55 45 30 5

b-Continuous: not have gaps or interruption, e.g. S. cholesterol & weight (i.e. we can say 25.8 kg in weight). glucose level. Variable has unit. Hb,

2-Qualitative: that which can't be measured in usual sense ,but we can describe them in categories &there is no numerical value. e.g. eye colors ,type of anemia, blood group ,socio- economic status

Independent and Dependent variable The two main variables in an experiment are the independent  and dependent variable. An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. A dependent variable is the variable being tested and  measured in a scientific experiment.

Four Levels of Measurement Measurements and Measurement Scales Measurement : this may be defined as the assignment of numbers to objects or events according to a set of rules. Four Levels of Measurement

1-The Nominal Scale: the lowest measurement scale is the nominal scale, as the name indicates it consists of ''naming'' observations or classifying them into mutually exclusive and collectively categories . Medical diagnosis Male – female Country of Birth Race, Blood group

2-Ordinal Scale allow us to rank order the items we measure in terms of which has less and which has more of the quality represented by the variable, but still they do not allow us to say "how much more.” A typical example of an ordinal variable is the socioeconomic status of families.

Ordinal Scale data Examples Pain level (Mild, Moderate, Severe) Tumors (Stage 0, ……, IV) Arthritis (Class 1, ……, 4 ) Military Rank (Lt., Capt., Maj., Col., General)

due to the presence of minus numbers, 3-Interval scale: each measurement is assigned to number of categories that are equally spaced with no true zero point, it does not begin from zero due to the presence of minus numbers, e.g. temperature. With this scale ,it is not only possible to order measurement , but also the distance between any two measurements is known , the difference between measurement of 20 & measurement of 30 is equal to the difference between measurement of 30 &40.

T he interval scale unlike the nominal and ordinal scales is a truly quantitative scale.

Frequency Class interval 11 30 – 39 46 40 – 49 70 50 – 59 45 60 – 69 16 70 – 79 1 80 – 89 189 Total