Introduction to Biostatistics HLSC 2P07

What is biostatistics?

Application of statistics to biological sciences, medical/health sciences and related disciplines.

• Collecting, summarizing, and interpreting information

• Making inferences that appropriately account for uncertainty

Case Report and Case Series?

• a case report is a very detailed report of the specific features of a particular participant or case

• a case series is a systematic review of the interesting and common features of a small collection, or series, of cases

Cross sectional study

We survey a population and for each participant we determine the exposure and the outcome simultaneously

• exposed and have disease

• Exposed and no disease

• Not exposed and have disease

• Not exposed and no disease

Case control study

We select participants with (cases) and without (controls) disease

And then determine if they are exposed or not exposed

Cohort study

Select participants with and without the exposure

Determine if they develop the disease or not

Randomized controlled trial

Assign participants to intervention vs control groups

Determine if they develop the outcome or not

Population vs sample

Population: complete collection of all elements to be studied

Sample: part of population

Probability vs non-probability sampling

Probability sampling

• selection of unit is a random process

• Unbiased representation of a group

Non-random sample

• Biased

• Examples include convenience, purposive, snowball

Parameter vs statistic

Parameter: a numerical measure that describes some characteristic of a population

Statistic: a numerical measure that describes some characteristic of a sample

What is data?

Pieces of information that result when measurements are obtained

Quantitative data vs qualitative data

Qualitative : can be described but not measured, non-numeric characteristic

Quantitative : numbers, can be statistically manipulated

• discrete variable is a countable number

• Continuous variable is a countless number of valuesb

Levels of measurement

Nominal

• data consists names, labels, categories- cannot be ordered

Ordinal

• data can be ordered but value differences meaningless

Interval

• Data values are meaningful but no natural zero

Ratio

• data values are meaningful and there is natural zero

What is a variable?

A quantity that can be given any value