t-tests Flashcards
Difference between descriptive and inferential statistics
Descriptive statistics presents findings (graphs)
inferential statistics make predictions (hypothesis testing, ANOVA, etc)
What is Null Hypothesis Significance Testing (NHST)
- Null hypothesis (H₀) is implied
-no findings = no effect - Alternative hypothesis (H₁) is suggested, which implies an effect
-based on research
-either 1 or 2 tailed
Null hypothesis can ONLY be rejected if SIGNIFICANT
What do p-values do
Denote significance
What’s the meaning of p-value < 0.05?
Reject null hypothesis
What’s up if p-value > 0.05?
Fail to reject null hypothesis
picky wording, effect might still exist. just not proven in this study
What do t-tests do
- Compare two (2) means
-sees if they’re significantly different from each other
What does this R code run
t.test(DV ~ IV, data = df, var.equal = FALSE)
Bold should be replaced to actual variable names
eg sleep, drink, mydata
R code to run a t-test (specifically independent)
What does this R code run
1 mydata %>%
2 cohens_d(DV ~ IV, var.equal = FALSE)
Bold should be replaced to actual variable names
eg sleep, drink, mydata
R code to run cohen’s d (specifically for independent t test)
What does this R code run
hist(df$DV[df$IV == “group name”])
Bold should be replaced to actual variable names
eg sleep, drink, mydata, water
R code to create a histogram
Wtf is this
Code for Shapiro-Wilk test
Checks if shit is normally distributed or not
what is this
R code for repeated measures t test
what the schlawg is this
cohen’s d for repeated t test
specifically repeated
note the: paired = TRUE
What the hell
how to run a one sample t-test
