RMA W10-11 Flashcards
What are z-scores?
Z-scores allow us to compare values from different data sets.
How do you calculate a z-score?
z= x- mean/SD
How do you interpret a z-score?
A z-score tells you how many standard deviations from the mean a value is. A smaller number indicates being closer to the mean.
What does a table entry give you?
It gives you the area to the left of the z-score. Subtracting it from 1 gives the area to the right.
What is the chi-square test for goodness of fit(x^2)?
It’s used for categorical data/nominal variables to answer questions about the proportions of a population distribution.
What is the formula for the χ^2 statistic?
∑((fobserved−fexpected)^2)/ fexpected)
What is the degrees of freedom for the χ^2 test for goodness of fit?
df=𝐶−1, where C is the number of categories.
What is the χ^2 test of independence?
It determines if two separate variables are linked or associated. The null hypothesis suggests there is no relationship.
How do you calculate the expected frequency in the χ^2 test of independence?
fexpected=column total×row total/total sample number
How do you calculate degrees of freedom in the χ^2 test of independence?
df=(r−1)×(c−1), where r and c are the number of rows and columns, respectively.
What is another term for p=0.05?
It’s often denoted as 𝛼 = alpha
What is statistical inference?
Statistical inference allows making inferences about a population from sample data.