categorical variable
a variable that names categories (whether with words or numerals wins or loss)
numerical variable
variables that take on values that are indicated by numbers
test statistic
a measure calculated from a performance that is used as evidence in a hypothesis test
P-value
measures how likely it is to get a test statistic at least as extreme as the observed test statistic by random chance, assuming that the null hypothesis is true. The results of a simulation provide an estimate of the p-value
confounded variables
when we aren't certain which variable is causing the difference we have observed
Control
keeping conditions exactly the same for each trial, except for the treatments being compared
statistically significant
if random chance is not a plausible explanation for observed performances
independent
if his or her ability to be successful is the same following a success and following a failure
significance level
A predetermined level of evidence that is required to essentially rule out random chance as a plausible explanation
Type 1 error (false positive)
when we reject the null hypothesis and the support the alternative hypothesis when in reality the null hypothesis is true
Type 2 error (false negative)
when we fail to reject the null hypothesis and do not decide to support the alternative hypothesis when in reality the alternative hypothesis is true
Distribution
the possible outcomes of a variable and how often it takes those outcomes
mean
the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores
range
the difference between the highest and lowest scores in a distribution
Median
the middle score in a distribution; half the scores are above it and half are below it
Interquartile Range (IQR)
Q3-Q1
Q1
Sets the lowest 25% of data points apart from the upper 75%
Q3
Sets the upper 25% of data points apart from the lower 75%
Outliers
extreme values that don't appear to belong with the rest of the data
performance
an observed value that describes what a person actually did in a specific context
ability
is a true but unknown value that describes what a person would do if given an infinite number of opportunities in the same context
Law of Large Numbers
the larger the number of individuals that are randomly drawn from a population, the more representative the resulting group will be of the entire population
Correlation doesn't imply causation
there is an infinite number of third variables
Null Hypothesis (H0)
A statement of "no difference.
alternative hypothesis
The hypothesis that states there is a difference between two or more sets of data.
sample size
The number of subjects used in an experiment or study. Generally, the larger the better.