test_k.R

teens <- read.csv("snsdata.csv")
str(teens)
table(teens$gender)
table(teens$gender, useNA = "ifany")
summary(teens$age)
teens$age <- ifelse(teens$age >= 13 & teens$age < 20,
                    teens$age, NA)
summary(teens$age)
teens$female <- ifelse(teens$gender == "F" &
                         !is.na(teens$gender), 1, 0)
teens$no_gender <- ifelse(is.na(teens$gender), 1, 0)
table(teens$gender, useNA = "ifany")
table(teens$female, useNA = "ifany")
table(teens$no_gender, useNA = "ifany")
mean(teens$age)
mean(teens$age, na.rm = TRUE)
aggregate(data = teens, age ~ gradyear, mean, na.rm = TRUE)
ave_age <- ave(teens$age, teens$gradyear, FUN =
                 function(x) mean(x, na.rm = TRUE))
teens$age <- ifelse(is.na(teens$age), ave_age, teens$age)
summary(teens$age)
library(stats)
interests <- teens[5:40]
interests_z <- as.data.frame(lapply(interests, scale))
set.seed(2345)
teen_clusters <- kmeans(interests_z, 5)
teen_clusters$size
teen_clusters$centers