We will explore diamonds dataset, history, and use EDA to create quantitative analysis.

Welcome

• Salomon, data analyst at Facebook, will make EDA to explore diamond.
• In the end, we will know, given the diamonds, is it a good deal or not.
• Wel also be able to predict the price of given diamonds.

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Scatterplot Review

library(ggplot2)
data(diamonds)
names(diamonds)

##  [1] "carat"   "cut"     "color"   "clarity" "depth"   "table"   "price"  
##  [8] "x"       "y"       "z"

ggplot(aes(x=carat, y = price),
       data = diamonds)+
  geom_point()+
  coord_cartesian(xlim=c(0,quantile(diamonds$carat,0.99)),
                  ylim=c(0,quantile(diamonds$price,0.99)))+
  stat_smooth(method = "lm")

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Price and Carat Relationship

• There are fix relationship between carat and price
• Same carat may have higher price, but it depends on the other variables

• More weight of carat, the higher price, but not go any lower

• We can see that some exponential increase as the price go higher.
• diversion increase as carat higher and price higher.

• By using linear model, we may have off predicting the price(too bias!)

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Frances Gerety

• We can’t just input the diamond data and pop the price.
• The diamonds’ price itself has each background story related to it.
• First found south africa.
• Earlier diamonds only found in India and Brazil. Back then, diamonds only priced by its supply.
• Then the biggest diamonds cartel build in US and control the diamonds market, De Beers which advertise the diamonds in many other way

A diamonds is….. FOREVER

• Diamonds earlier only for the rich, but the slogan, which made by Frances Gerety, quote “A diamonds is forever” which point to enggagement should make diamond engagement ring.

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The Rise of Diamonds

• The slogan itself is powerful. It create the intense of the diamonds.
• They do that, as earlier said, the company has create a cartel and monopolize the diamonds in South Africa.
• Since then they give movie star a diamond, price vary giving each other between selebrity.
• They can even make Britsh Royal to use diamonds in their crown over other gems.
• They create the engagement ring should wear diamonds. And advertise what are the price of diamonds compared to what men achieve in life.
• Engagament symbol at Facebook
• Movie engagement most contain diamond

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ggpairs Function

• each variable plotting other variable in ggpairs
• qual qual, scat qual auan
• group histogram in top left qual-qual group by x
• boxplot qual-quan
• correlation at lower right quan-quan

# install these if necessary
# install.packages('GGally')
# install.packages('scales')
# install.packages('memisc')
# install.packages('lattice')
# install.packages('MASS')
# install.packages('car')
# install.packages('reshape')
# install.packages('plyr')

# load the ggplot graphics package and the others
library(ggplot2)
library(GGally)
library(scales)
library(memisc)

## Loading required package: lattice
## Loading required package: MASS
## 
## Attaching package: 'memisc'
## 
## The following object is masked from 'package:scales':
## 
##     percent
## 
## The following objects are masked from 'package:stats':
## 
##     contr.sum, contr.treatment, contrasts
## 
## The following object is masked from 'package:base':
## 
##     as.array

# sample 10,000 diamonds from the data set
set.seed(20022012)
diamond_samp <- diamonds[sample(1:length(diamonds$price), 10000), ]
ggpairs(diamond_samp, params = c(shape = I('.'), outlier.shape = I('.')))