Week Four Flashcards
(19 cards)
Define the independent/explanatory variable
The variables which explain or predict performance of the outcome.
Define the dependent variable.
The outcome variable, its value depends on the input.
Define the constant
A combination of different constants.
What type of data do bar or column charts graph?
Categorical or the means for different groups
What type of data do line graphs chart?
Temporal or time series data
What type of data do histograms graph?
Continuous data only
What do box plots graph?
The median, the interquartile range and outliers to compare them.
Define correlation
The degree and direction of relatedness between two variables.
What is the correlation coefficient (r)?
The degree to which two sets of numbers go together and the strength of the association. We can calculate if we have values for two variables.
If r is positive what direction is the association?
The association is in the same direction.
If r is negative what direction is the association?
The association is in opposite directions.
What is coefficient of determination (r-squared)?
The proportion of the variance of one variable predictable from the other variable. It is the square of r.
What does r-squared = 100% tell us about the variation of the variables?
That the line of best fit passes exactly through every point.
What would we say if r-squared = 0.8 or 80%?
80% of the variation in y can be explained by the linear relationship between x and y, as described by the regression equation.
What is Spearman’s rho or p?
Used to examine the association of ordinal variables. We can use p where the relationship is nonlinear and monotonic.
Define alpha
The alpha is the likelihood of being incorrect when we say that our sample reflects a relationship in the population.
What is the typical alpha level set as?
0.05 or 95% level of confidence.
What do we do if the p-value is greater than the alpha?
If the p-value is larger than the alpha then we assume that the correlation occurred by change so we accept the null hypothesis of no relationship between the variables.
What does the p-value denote?
The p-value denotes the probability that the correlation occurred by chance.
