install.packages("moments")
# IST 687 - Applied Data Science
# Homework 4
# Step 1: Write a summarizing function to undersand the distribution of a vector
# Question 1 and 2
printVecInfo <- function(v){
  a<-mean(v)
  b<-median(v)
  c<-min(v)
  d<-max(v)
  e<-sd(v)
  f<-quantile(v,probs=0.05)
  g<-quantile(v,probs=0.95)
  library(moments)
  h<-skewness(v)
  cat("mean:",a,"\nmedian:",b,"\nmin:",c,"max:",d,"\nsd:",e,"\nquantile (0.05 - 0.95):",f,"--",g,"\nskewness:",h)
}
# Question 3
vect <- c(1,2,3,4,5,6,7,8,9,10,50)
printVecInfo(vect)

# Step 2: Creating Samples in a Jar
# Question 4
blu <- "blue"
red <- "red"
v.blu <- replicate(50,blu)
v.red <- replicate(50,red)
jar <- c(v.blu, v.red)
# Question 5
length(jar[jar==red])
# Question 6
jarSam <- sample(jar,10,replace=TRUE)
jarSam
numRed <- length(jarSam[jarSam==red])
perRed <- numRed / 10 *100
cat("Number of red marbles:",numRed,"\nPercent red marbles:",perRed,"%")

# Question 7a
sam <- function(j){
  samp <- sample(j,10,replace=TRUE)
  num <- length(samp[samp==red])
  return(num)
}
sam(jar)
# Question 7b
mean(replicate(20,sam(jar)))
# Question 7c
sampleMeans <- replicate(20,mean(replicate(20,sam(jar))))
printVecInfo(sampleMeans)

hist(sampleMeans)
# Question 8
sam2 <- function(j){
  samp <- sample(j,100,replace=TRUE)
  num <- length(samp[samp==red])
  return(num)
}
sam2(jar)
mean(replicate(100,sam2(jar)))
sampleMeans2 <- replicate(20,mean(replicate(100,sam(jar))))
printVecInfo(sampleMeans2)
hist(sampleMeans2)
# Question 9
sam3 <- function(j){
  samp <- sample(j,100,replace=TRUE)
  num <- length(samp[samp==red])
  return(num)
}
sam3(jar)
mean(replicate(100,sam3(jar)))
sampleMeans3 <- replicate(100,mean(replicate(100,sam(jar))))
printVecInfo(sampleMeans3)
hist(sampleMeans3)

# Step 3: Explore the airquality dataset
# Question 10
aq <- airquality
# Question 11

any(is.na(aq))
length(aq[aq=='NA'])
str(aq)
aq <- na.omit(aq)
str(aq)

rownames(aq) <- NULL
# Question 12
ozone <- aq[,1]
wind <- aq[,3]
temp <- aq[,4]
printVecInfo(ozone)
hist(ozone)
printVecInfo(wind)
hist(wind)
printVecInfo(temp)
hist(temp)