Into to statistics Flashcards
Give examples of summary statistics
Means
Medians
Standard deviations
Basic graphs
What is statistics?
1) a numerical summary of data
2) the science of collecting, summarising, presenting and interpreting data
What is a variable?
A factor that varies within a set of data
What is a response variable?
Describes the condition of an individual / subject AKA outcome measures / dependent variables
What is an explanatory variable?
Measures that might explain the condition of an individual / subject AKA predictor / independent variables
What is a confounder variable?
Measures that might obscure the relationship between response and explanatory variables (they are associated with the response and explanatory variable under study)
What is qualitative data?
Non-numeric and splits individuals into categories
Give examples of non-ordered qualitative data?
Smoker, non-smoker
Blood type
Give examples of ordered qualitative data?
Small, medium, large - size groups
What is quantitative data?
Information that is intrinsically numeric
What kind of graphs should be used for qualitative data?
Bar charts
Pie charts
What is the median?
The central value in a data set
What is the most commonly used measure of spread of data?
Standard deviation
What can we infer, if the mean of a sample is greater than the median?
The sample is positively skewed
What can we infer, if the mean of a sample is lesser than the median?
The sample is negatively skewed
Why is the median a better measure of central tendency if a data set is skewed?
Because it is not influenced by a small number of extreme observations
What is a histogram?
A graphical display of frequency distribution
What is a dot plot?
A graphical display of frequency distribution, where a dot is placed on the horizontal scale at each value in the data set, stacking points they are close together to form an impression of their density
When would a dot plot be preferable over a histogram?
When the data set is small
What type of graph would be used to compare two quantitative variables directly?
Scatterplot
