1st Slide Flashcards
Nominal scale
Data divided into different categories
E.g. Male/female, black/red, etc
Ordinal scale
Data divided into categories that can be ranked
E.g. good, better, best or very satisfied, satisfied, not satisfied.
Interval scales
Data that can be ranked
E.g. temperature reading in Celsius. Human body temp.
What is a ratio scale?
Ratio scale applies to data that can be ranked. All arithmetic operations (+, -, / or x) can be done. (There is an absolute or inherent zero)
Example: Height, weight, distance, duration etc. Zero weight is meaningful, and 10kg is twice as heavy as 5kg bag.
What does the scale of measurement determine?
The scale determines the amount of information contained in the data. It determines the mathematical operations that can be performed on the variables in the data set. The mathematical operations in turn determine which statistical measures can be applied to the data.
University of Ghana
What are the four scales of measurement?
NOMINAL, ORDINAL, INTERVAL, RATIO
University of Ghana
Which scale of measurement includes the terms ‘First, second, third, fourth’?
Ordinal scale
University of Ghana
What scale of measurement includes ‘Room 109, Room 100’?
Nominal scale
University of Ghana
What is the starting point of any statistical analysis?
Identifying the most appropriate source of data
Biases, ambiguities, and errors may flaw data collected. Even the most sophisticated statistical methods will not produce accurate information.
How are data sources classified?
Data sources are classified as
1. Primary
2. Secondary
A source is primary if the data collector is the one using the data for analysis. A source is secondary if one organization or individual has compiled the data to be used by another organization or individual.
What is a primary source of data?
A source is primary if the data collector is the one using the data for analysis.
E.g. Administrative records, Government statistics, Company records, published information (internet, publications)
What are the advantages and disadvantages of a primary source of data?
Advantage: Satisfy the specific needs or interest of user. User has control of what data to collect.
Disadvantage: Difficult, costly and time consuming to collect. May be labour intensive.
GHANA
What is a secondary source of data?
A source is secondary if one organization or individual has compiled the data to be used by another organization or individual.
GHANA
What are the advantages and disadvantages of a secondary source of data?
Advantage: Less expensive. Immediately available.
Disadvantage: May not satisfy needs of user. May not have complete information. No control over methods used for collection and accuracy of data.
GHANA
What are the primary data sources in biostatistics?
Primary data source may be obtained from Experimental or Observational studies
Data collected through the conduct of an experiment