# R for Psychological Research, Lesson 2: Objects & functions
# Code from the lesson page, in order. Run it line by line with Ctrl+Enter (Cmd+Enter on a Mac).
# Lines that start with # are comments: R ignores them.


# ---- Objects: values with a name ----

age <- 21
age
age + 1


# ---- Vectors: many values ----

exam <- c(73, 75, 52, 43, 88, 67)
exam

exam[2]
exam[c(1, 3)]
exam[2:4]
exam + 5


# ---- Functions ----

mean(exam)
median(exam)
sd(exam)
min(exam)
max(exam)
length(exam)

round(sd(exam), digits = 1)


# ---- Text and TRUE/FALSE ----

gender <- c("Male", "Male", "Female", "Male", "Female", "Male")
gender


# ---- Yes/no questions ----

exam > 70
sum(exam > 70)
exam[exam > 70]


# ---- Missing values: NA ----

sleep <- c(6, 6, NA, 5.8, 5.5, 6.5)
mean(sleep)
mean(sleep, na.rm = TRUE)