statistics Flashcards
what are the 2 types of stats?
- Descriptive/distribution statistics
- Inferential statistics
what is descriptive/distribution statistics
Summarize and describe characteristics of a data set (ex; avg course grade in the class)
Inferential statistics
Tells us how confident we can be in drawing conclusions/inferences about a population based on findings obtained from a sample (ex; does your grade in 104 predict your 205 grade?)
Measures of central tendency
Measures that describe a distribution in terms of a single statistic that is in some way “typical” of the sample as a whole
mode vs mean vs median
Mode: The most frequent response in a distribution
Mean: The mathematical average of a set of scores
Median: When ordered from lowest value to highest value, the score that is in the middle of the distribution
Measures of variability
Measures that provide information about the spread of scores in a distribution
Range
The difference between the highest and lowest score in a distribution
-may not be informative
Variance
The average of the squared deviation scores about the mean
Standard deviation
A common measure of variation around the mean
Normal curve
A symmetrical bell-shaped curve that represents a theoretical distribution of scores in the population.
Inferential statistics
Studies using experimental methods, correlations, or other hypothesis testing procedures use inferential statistics, based on probability
Statistical significance
A term that suggests that it is unlikely that a particular finding occurred by chance alone
-Does not address how large or small an effect is, just that there is likely an effect
p-value
The probability of finding the observed, or more extreme, results when there is no true effect
Practical significance
Statistical significance only tells us there is (likely) an effect
Does not tell us how much of an effect or its practical value
Effect size
How large of an effect there is
