Statistics in Allied Health Flashcards
What is the purpose of statistics?
- control sources of variation; detect outliers
- analysis of data
- interpret the statistical and practical significance of results
- in making scientifically sound decisions and communicating them
What are descriptive statistics?
- describe what was observed in the sample numerically or graphically
What are some common numerical descriptors?
Mean and standard deviation for continuous data types (i.e. age)
Frequency and percentages are useful for describing what data?
categorical data i.e. gender
What is inferential statistics?
uses patterns in the sample to draw inferences about the population represented
What are some examples of inferential statistics?
- Hypothesis testing: yes/no questions about the data
- Estimation: estimating numerical characteristics of data
- Correlation: describing associations within the data
- Regression analysis: modelling relationships with the data
What can inferential stats be used for?
- forecasting, prediction and estimation of unobserved values either in or associated with population studies
What is a sample as compared to a population?
- sample is a subset of the population
- population is a group of people with a common trait
What is one of the most important factors of the sample?
It’s representation on behalf of the population as we use the sample to infer about the population.
What are the two types of sample selections?
- probabilistic: everyone has a similar chance of being selected
- non-probabilistic: not everyone has the same chance of being selected
What are some probabilistic sampling methods?
- simple/stratified random sampling
- systematic random sampling
What are some non-probabilistic sampling methods?
- convenience sampling
- snowball sampling
- purposive sampling
What are the 4 types of variables?
Nominal, ordinal, interval and ratio
What is nominal data?
numbers given to a variable have no significance
What is an example of nominal data?
0 = male, 1 = female
What is a dichotomous variable?
a variable (nominal) with two possibilities
What is ordinal data?
the order of the number holds significance
Give an example of ordinal data
- pain scale
- likert scale
What is interval data?
continuous variable, the value of 0 does not indicate the absence of a quality
Give an example of interval data
temperature
What is ratio data?
continuous variable where the value of 0 does indicate the absence of a quality
What is an example of ratio data?
weight
When is a continuous variable classified as discrete?
if it is restricted to a fixed number of values
What is raw data?
value the same unit as it was measured in
What is scaled data?
units of measurement given a relative value that makes it comparable to other values in the general population
What is the criterion variable/outcome variable?
The presumed effect in a study
What is the predictor variable/covaraite
The presumed cause in a experimental study (potentially associated with the outcome variable)
What is relative frequency?
The frequency in a subgroup relative to the total number
What are mutually exclusive variables?
Variables that don’t overlap
What is a example of a mutually exclusive variable?
age
What data does bar graphs show?
crude data not relative data
What data does pie graphs show?
can show both crude and relative data
What do scatter plots show?
correlation between two continuous variables simultaneously
What do line graphs show?
time trends where the x axis shows the unit of time and the y axis displays the values of the variable being plotted