LECTURE 4 - quantitative data analysis 1 Flashcards
Descriptive statistics
Describing sample on the basis of data collected, not drawing conclusions of population
Inferential statistics
Drawing conclusions about a population on the basis of a sample. Require a representative sample (large sample)
Hypothesis
a statement concerning a population that may or may not be true, and constitutes an inference or inferences about a population, drawn from sample information
Type I error
occurs when we reject a true null hypothesis (when the jury convicts an innocent person)
Type II error
Occurs when we do not reject a false null hypothesis (when one accepts a null hypothesis that is actually false) (when the jury acquits a guilty person)
The process of hypothesis testing (4)
- Hypothesis formulation
- Specification of significance level
- Selection of appropriate statistical tests
- Calculation of the test statistic and acceptance or rejection of the hypothesis
Setting of significance level
- 0.1
- 0.05
- 0.01 or 0.001
- 1 -> consequences of a type 2 error are most severe
- 05 -> Consequences of making type 1 and 2 error are equally severe
- 01 or 0.001 -> consequences of type 1 error are most severe
Categorical data (2)
- Nominal
- Ordinal
Quantifiable data (2)
- Interval
- Ratio
Bar chart
- Nominal
- Ordinal
Pie chart
- Nominal
Histogram
- Interval
- Ratio
Frequency polygon
- Interval
- Ratio