1They are used in hypothesis testing to determine whether a predictor variable has a statistically significant relationship with an outcome variable, or to estimate the difference between two or more groups.
statistical tests primarily
2What hypothesis do statistical tests assume by default?
They assume a null hypothesis of no relationship or no difference between groups.
3What value estimates how likely it is that you would see the observed difference if the null hypothesis were true?
The p-value (probability value).
4What are the two main types of quantitative variables?
Discrete variables (counts of individual items) and continuous variables (measurements of continuous or non-finite values).
5What are the three types of categorical variables?
Binary variables (yes or no outcomes), nominal variables (groups with no rank or order), and ordinal variables (groups ranked in a specific order).
6In an experiment, what is the variable that you manipulate to affect the outcome?
The independent variable, also known as the treatment variable.
7In an experiment, what is the variable that represents the outcome?
The dependent variable, also known as the response variable.
8What type of variable hides the true effect of another variable because it hasn't been controlled?
A confounding variable.
9What are the three common assumptions that statistical tests make about data?
Independence of observations, homogeneity of variance, and normality of data.
10Which parametric tests look for cause-and-effect relationships?
Regression tests.
11Which parametric test is used when comparing the means of precisely two groups?
T-tests.
12Which parametric tests are used when comparing the means of more than two groups?
ANOVA and MANOVA tests.
13What type of test is a Pearson’s chi-square test?
It is a statistical test for categorical data used to determine whether observed data differ significantly from expected results.
14Which test should you use to check if the frequency distribution of one categorical variable differs from expectations?
The chi-square goodness of fit test.
15Which test should you use to determine whether two categorical variables are related to each other?
The chi-square test of independence.
16What is the formula to calculate the degrees of freedom for a chi-square goodness of fit test?
df = number of groups – 1.
17What is the formula to calculate the degrees of freedom for a chi-square test of independence?
df = (number of variable 1 groups – 1) * (number of variable 2 groups – 1).
18What statistical test uses the chi-square test statistic to determine whether proportions are equal for a related pair of categorical variables that each have two groups?
McNemar’s test.