Unit 0 Vocab- Statistical Concepts Flashcards
Mean
Arithmetic average, which can be skewed by fringe scores.
Mode
Most frequently occurring score in a data set (rarely useful).
Median
The mid-point of the data set (N).
N value
A score that represents the population (# of scores).
Percentile ranking
Tells how well you did compared to others (scoring as well as or better than x% of people).
Range
The distance between the highest and lowest number in a data set.
Regression to the mean
Returning to the average after an event unusually high or low (such as having a lucky day)
Effect size
How much the independant variable effects the dependant variable.
Statistical significance
The possibility that observed differences in data are due to chance.
P value
The statistical significance number in equations.
When P is less than or equal to 5% (0.5)
P<= .05
This means the statistic is definitely by chance.
Bell curve
A normal bell cure is when the mean, median, and mode are all the same.
Standard deviation
How far a score is from the middle of the curve.
Bimodal distribution
A bell curve that has two peaks because the data has two modes (e.g. restaurant rush at both lunch and dinner).
Positive correlation
As one result goes up on a scatterplot, so does the other, and vice versa.
Causation
When an event causes another to happen more or less often (not the same as correlation).
Negative correlation
If one result on a scatterplot goes down, the other goes up, and vice versa.
Correlation coefficient
It ranges from 1 (positive) to -1 (negative).
Scatterplot
Plot points to determine if there is a correlation between two variables and which type of correlation.
“0” correlation
There is no relationship between two variables.
Correlation research design
It investigates the relationship between two variables.
Directional problem
When you can’t tell which variable caused the other.
Illusory correlation
Seeing a relationship where none exists (e.g. superstition).
3-variable problem
When a third, confounding variable is added to an experiment that throws it off.
Confounding variables
An external factor in an experiment that affects both the independent and dependant variables.
Histogram
A bar graph
X and Y axes
On a graph X is horizontal and Y is vertical.
Inferential statistics
Determining how reliable and statistically significant the statistics are. To see if a result can be generalized to the whole population.
Descriptive statistics
Numbers that are true, but can be manipulated to tell different stories. Summarizes data and results.
When the mean is greater than the median (mean > median)
There are higher fringe scores.
When the median is greater than the mean (median > mean)
There are lower fringe scores.
Population percentage for 1SD, 2SD, 3SD normal curve (SD= Standard divination)
1SD= 2/3 (around 68%)
2SD= 95%
3SD= 99%
