Chapter 3: Stats Flashcards
Bimodal distribution
2 modes in a distribution
Mean
Mathematical average of the distribution of scores
Median
Middle score in the distribution
Mode
Most frequently occurring score in a distribution
Multimodal distribution
2 or 3 more modes in your distribution
Frequency distribution
How often a score occurs in a set of data
Nominal scale of measurement
The data is categorical. It assigned observations into independent categories and then counting the frequency of occurrence within each of the categories creates a nominal scale.
Ordinal scale of measurement
Involves the rank order system.a scale in which the scores index are only relative amounts of rank order. When we discuss rank order in a horse race we are using ordinal data.
Interval set of measurement
Equal differences in scores represent equal differences in amount of the property measured.
Ratio scale of measurement
All the properties of an interval scale with the additional property of zero indicating the total absence of the quantity being measured.
Measures of central tendency
Mean, median, mode
Range
Difference between the high score and low score in a distribution range.
Variance
Statistical concept that tells you the spread of scores within a distribution.
Standard deviation
Calculated by taking the square root of the variance
Normal distribution
Arrangement of a data set in which most values cluster in the middle of the range and tapper odd symmetrically toward either extreme.
Normal curve
A graphical representation of a normal distribution
Skewed distribution
Majority of scores fall in either the high or low end not middle
Positively skewed distribution
Most of the scores fall below the mean
Negatively skewed distribution
More scores fall above mean
Correlations
Tell us the relationship between two variables
Positive correlation
Variables are said to be positively correlate when a high score on one is accompanied by a high sore on the other (direct relationship)
Negative correlation
High score on one is accompanied by low score on the other. An inverse relationship.
Zero correlation
No relationship between variables.
Correlation coefficient
Describing the relationship between any two variables
3 measures of central tendency
Mode median and mean
Measures of variance
Standard deviation and range
Mode in this data set: 25,44,45,56,79,83, 45
45
What is the mode: 25, 44,44,45,56,79,79,83
44 and 79
Median in this data set: 25,44,45,56
44.5
Median in this data set: 25,44,45,56,79
45
Mean of this data set:25,44,45,45,56,59
49
