R Bridge Program- Week 2 Assignment

by William Outcault

Read gravity.csv as “raw” file.

gravity <- read.csv('https://raw.githubusercontent.com/wco1216/gravity/master/gravity.csv',TRUE,',')

Summary of gravity data.

summary(gravity)

##        X            g              series     
##  Min.   : 1   Min.   : 35.00   Min.   :1.000  
##  1st Qu.:21   1st Qu.: 76.00   1st Qu.:3.000  
##  Median :41   Median : 78.00   Median :5.000  
##  Mean   :41   Mean   : 78.89   Mean   :4.815  
##  3rd Qu.:61   3rd Qu.: 83.00   3rd Qu.:7.000  
##  Max.   :81   Max.   :109.00   Max.   :8.000

Mean & median of ‘g’ feature.

mean(gravity$g)

## [1] 78.88889

median(gravity$g)

## [1] 78

Mean & median of ‘series’ feature.

mean(gravity$series)

## [1] 4.814815

median(gravity$series)

## [1] 5

Create subset of gravity data, rename the columns and display the summary of the subset.

grav_subset <- data.frame(gravity[c(1:15), c("g", "series")])
colnames(grav_subset) <- c("sub g", "sub series")
summary(grav_subset)

##      sub g          sub series   
##  Min.   : 35.00   Min.   :1.000  
##  1st Qu.: 72.00   1st Qu.:1.000  
##  Median : 87.00   Median :1.000  
##  Mean   : 81.93   Mean   :1.467  
##  3rd Qu.: 99.00   3rd Qu.:2.000  
##  Max.   :109.00   Max.   :2.000

Mean & median of the ‘g’ feature in the subset.

mean(grav_subset$`sub g`)

## [1] 81.93333

median(grav_subset$`sub g`)

## [1] 87

Mean & median of the ‘series’ feature in the subset.

mean(grav_subset$`sub series`)

## [1] 1.466667

median(grav_subset$`sub series`)

## [1] 1

Replace 3 values in the subset.

grav_subset$`sub series`[grav_subset$`sub series`==1] <- 1000
grav_subset$`sub series`[grav_subset$`sub series`==2] <- 2000
grav_subset$`sub g`[grav_subset$`sub g`==100] <- 'N/A'

Display result of previous steps.

grav_subset

##    sub g sub series
## 1     76       1000
## 2     82       1000
## 3     83       1000
## 4     54       1000
## 5     35       1000
## 6     46       1000
## 7     87       1000
## 8     68       1000
## 9     87       2000
## 10    95       2000
## 11    98       2000
## 12   N/A       2000
## 13   109       2000
## 14   109       2000
## 15   N/A       2000