6.1 Sampling and 6.2 Presentation of Data Flashcards
Univariate analysis
Involves a single variable
Qualitative data
The qualities of something
Quantitative data
Numbers, anything that can be counted or measured
Discrete
Exact numerical values (fixed values)
Continuous
Measured values (within a range)
Population
All members of a defined group
Sample
A subset of the population
Convenience sampling
You select those members of the population who are most easily accessible or readily available
Simple random sampling
Each member of the population has an equal chance of being selected
Systematic sampling
You list the members of the population and select a sample according to a random point and a fixed point
Stratified sampling
The population is divided into smaller groups known as strata. The strata are formed based on members’ shared characteristics. You then choose a random sample from each stratum and put them together to form your sample
Quota sampling
This is like stratified sampling but involves taking a sample size from each stratum which in proportion to the size of the stratum
Frequency table
When you have raw data, a frequency table is an easy way to view and organize your data quickly. Data can then be put into a bar chart or histogram
Bar chart
Suitable for discrete dates. Bars have gaps
Histogram
Suitable for continuous data. Bars have no gaps
Is favorite color qualitative or quantitative?
Qualitative
Is annual salary qualitative or quantitative?
Quantitative
Is shoe size discrete or continuous?
Discrete
Is time take to get home from school discrete or continuous?
Continuous
Identify the population and sample. “A recent study of 2625 elementary students found 28% live in a single-parent household”
Elementary students is the population and 2625 is the sample
What kind of sampling? “People in the same room as you”
Convenience
What kind of sampling? “Names in a hat”
Simple random
What kind of sampling? “Every 10th person in a line”
Systematic
What kind of sampling? “Separate by class, pick 20 from each”
Stratified
What kind of sampling? “100 females between the ages of 15 and 25”
Quota
When most of the data is on the right of a histogram, which way is it skewed?
Left (negative)
When most of the data is on the left of a histogram, which way is it skewed?
Right (positive)
When most of the data in a histogram is in middle, which way is it skewed?
Normal (centered)
Is a histogram used for discrete or continuous data?
Continuous
