AS1-2 Stock Dynamics

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library(dplyr)

Section-1 Summary Statistics

§ 1.1 Our five datasets all have the same number of observations. How many observations are there in each data set?

IBM = read.csv("data/IBMStock.csv")
GE = read.csv("data/GEStock.csv")
PG = read.csv("data/ProcterGambleStock.csv")
CK = read.csv("data/CocaColaStock.csv")
BE = read.csv("data/BoeingStock.csv")
IBM$Date = as.Date(IBM$Date, "%m/%d/%y")
GE$Date = as.Date(GE$Date, "%m/%d/%y")
CK$Date = as.Date(CK$Date, "%m/%d/%y")
PG$Date = as.Date(PG$Date, "%m/%d/%y")
BE$Date = as.Date(BE$Date, "%m/%d/%y")
str(IBM)

'data.frame':   480 obs. of  2 variables:
 $ Date      : Date, format: "1970-01-01" "1970-02-01" ...
 $ StockPrice: num  360 347 327 320 270 ...

nrow(IBM)

[1] 480

§ 1.2 What is the earliest year in our datasets?

min(IBM$Date)

[1] "1970-01-01"

§ 1.3 What is the latest year in our datasets?

max(IBM$Date)

[1] "2009-12-01"

§ 1.4 What is the mean stock price of IBM over this time period?

mean(IBM$StockPrice)

[1] 144.38

§ 1.5 What is the minimum stock price of General Electric (GE) over this time period?

min(GE$StockPrice)

[1] 9.2936

§ 1.6 What is the maximum stock price of Coca-Cola over this time period?

max(CK$StockPrice)

[1] 146.58

§ 1.7 What is the median stock price of Boeing over this time period?

median(BE$StockPrice)

[1] 44.883

§ 1.8 What is the standard deviation of the stock price of Procter & Gamble over this time period?

sd(PG$StockPrice)

[1] 18.194

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Section-2 Visualizing Stock Dynamics

§ 2.1 Around what year did Coca-Cola has its highest stock price in this time period? Around what year did Coca-Cola has its lowest stock price in this time period?

plot(CK$Date, CK$StockPrice, type='l')  # 1973 1980
abline(v=CK$Date[which.max(CK$StockPrice)], col='green')

abline(v=CK$Date[which.min(CK$StockPrice)], col='red')

§ 2.2 In March of 2000, the technology bubble burst, and a stock market crash occurred. According to this plot, which company’s stock dropped more?

plot(CK$Date, CK$StockPrice, type='l', col='blue', lwd=2)
lines(PG$Date, PG$StockPrice, col="green", lwd=2)

abline(v = as.Date("2000-03-01"), lty=3, col='orange')
abline(v = as.Date("1983-07-01"), lty=3, col='orange')

legend("topright",legend=c("Coke","P&G"),col=c('blue','green'),lwd=2)

§ 2.3 (a) Around 1983, the stock for one of these companies (Coca-Cola or Procter and Gamble) was going up, while the other was going down. Which one was going up?

# Coca-Cola

2. In the time period shown in the plot, which stock generally has lower values?

# Coca-Cola

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Section-3 Visualizing Stock Dynamics 1995-2005

§ 3.1 Which stock fell the most right after the technology bubble burst in March 2000?

plot(CK$Date[301:432], CK$StockPrice[301:432], 
     type="l", col="red", ylim=c(0,210))
lines(PG$Date[301:432],  PG$StockPrice[301:432],  col="blue")

lines(IBM$Date[301:432], IBM$StockPrice[301:432], col="green")
lines(GE$Date[301:432],  GE$StockPrice[301:432],  col="purple")

lines(BE$Date[301:432],  BE$StockPrice[301:432],  col="orange")
abline(v = as.Date("2000-03-01"), lty=3, col='gray')

abline(v = as.Date("1997-09-01"), lty=3, col='gray')
abline(v = as.Date("1997-11-01"), lty=3, col='gray')

§ 3.2 Which stock reaches the highest value in the time period 1995-2005?

# IBM

§ 3.3 In October of 1997, there was a global stock market crash that was caused by an economic crisis in Asia. Comparing September 1997 to November 1997, which companies saw a decreasing trend in their stock price? (Select all that apply.)

# P&G and Boeing

§ 3.4 In the last two years of this time period (2004 and 2005) which stock seems to be performing the best, in terms of increasing stock price?

# Boeing

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Section-4 Monthly Trends

§ 4.1 For IBM, compare the monthly averages to the overall average stock price. In which months has IBM historically had a higher stock price (on average)? Select all that apply.

tapply(IBM$StockPrice, format(IBM$Date,"%m"), mean) - mean(IBM$StockPrice)

     01      02      03      04      05      06      07      08      09 
 5.8634  8.3190  8.0577  7.7418  7.1272 -5.2844 -5.3080 -4.2296 -5.2865 
     10      11      12 
-7.0285 -6.3563 -3.6157 

§ 4.2 General Electric and Coca-Cola both have their highest average stock price in the same month. Which month is this?

sapply(list(BE=BE,CK=CK,GE=GE,IBM=IBM,PG=PG), function(df) {
  tapply(df$Stock, format(df$Date,"%m"), mean) - mean(df$Stock)
  })

          BE       CK       GE     IBM        PG
01 -0.081960  0.33876  2.74160  5.8634  1.913468
02  0.299299  0.70502  3.21730  8.3190  1.321238
03  0.289142  2.04162  3.84704  8.0577 -0.356910
04  0.453927  2.65915  5.17659  7.7418 -0.017809
05  1.544226  1.41385  1.56785  7.1272  0.155062
06  0.792321  0.78235 -2.83506 -5.2844 -0.311765
07 -0.039332 -1.04627 -2.57001 -5.3080 -1.058957
08  0.270174 -1.14959 -2.80036 -4.2296 -0.881853
09 -0.288080 -2.42949 -3.06437 -5.2865 -1.080671
10 -1.376899 -2.09086 -3.06454 -7.0285 -1.025482
11 -1.443030 -0.92705 -2.01471 -6.3563  0.751587
12 -0.419788 -0.29750 -0.20133 -3.6157  0.592091

§ 4.3 For the months of December and January, every company’s average stock is higher in one month and lower in the other. In which month are the stock prices lower?

# December