Exercise 1

require(dplyr, quietly = T, warn.conflicts = F)

carprice_df <- read.csv('https://raw.githubusercontent.com/mehtablocker/CUNY_bridge/master/carprice.csv')
carprice_df %>% summary()
##        X              Type      Min.Price         Price      
##  Min.   : 6.00   Compact: 7   Min.   : 6.90   Min.   : 7.40  
##  1st Qu.:17.75   Large  :11   1st Qu.:11.40   1st Qu.:13.47  
##  Median :29.50   Midsize:10   Median :14.50   Median :16.30  
##  Mean   :36.54   Small  : 7   Mean   :16.54   Mean   :18.57  
##  3rd Qu.:60.25   Sporty : 8   3rd Qu.:19.43   3rd Qu.:20.73  
##  Max.   :79.00   Van    : 5   Max.   :37.50   Max.   :40.10  
##    Max.Price      Range.Price       RoughRange         gpm100     
##  Min.   : 7.90   Min.   : 0.000   Min.   :-0.020   Min.   :2.800  
##  1st Qu.:14.97   1st Qu.: 1.700   1st Qu.: 1.705   1st Qu.:3.800  
##  Median :18.40   Median : 3.300   Median : 3.305   Median :4.200  
##  Mean   :20.63   Mean   : 4.092   Mean   : 4.089   Mean   :4.167  
##  3rd Qu.:24.50   3rd Qu.: 5.850   3rd Qu.: 5.853   3rd Qu.:4.550  
##  Max.   :42.70   Max.   :14.600   Max.   :14.600   Max.   :5.700  
##     MPG.city      MPG.highway   
##  Min.   :15.00   Min.   :20.00  
##  1st Qu.:18.00   1st Qu.:26.00  
##  Median :20.00   Median :28.00  
##  Mean   :20.96   Mean   :28.15  
##  3rd Qu.:23.00   3rd Qu.:30.00  
##  Max.   :31.00   Max.   :41.00
carprice_df$Price %>% mean(); carprice_df$Price %>% median()
## [1] 18.57292
## [1] 16.3
carprice_df$MPG.highway %>% mean(); carprice_df$MPG.highway %>% median()
## [1] 28.14583
## [1] 28

Exercise 2

carprice_filt_df <- carprice_df %>% sample_frac(0.5)

Exercise 3

carprice_filt_df <- carprice_filt_df %>% 
  rename(id = 1, 
         type = Type,
         min_price = Min.Price,
         price = Price,
         max_price = Max.Price,
         range_price = Range.Price,
         rough_range = RoughRange,
         gpm_100 = gpm100,
         mpg_city = MPG.city,
         mpg_highway = MPG.highway)

Exercise 4

carprice_filt_df %>% summary()
##        id             type     min_price         price      
##  Min.   : 6.00   Compact:3   Min.   : 8.40   Min.   :11.10  
##  1st Qu.:17.75   Large  :7   1st Qu.:13.03   1st Qu.:15.05  
##  Median :33.50   Midsize:6   Median :14.85   Median :18.25  
##  Mean   :37.71   Small  :2   Mean   :17.27   Mean   :19.45  
##  3rd Qu.:54.25   Sporty :3   3rd Qu.:19.50   3rd Qu.:20.73  
##  Max.   :79.00   Van    :3   Max.   :37.50   Max.   :40.10  
##    max_price      range_price      rough_range        gpm_100     
##  Min.   :12.20   Min.   : 0.000   Min.   :-0.020   Min.   :3.000  
##  1st Qu.:16.70   1st Qu.: 1.800   1st Qu.: 1.812   1st Qu.:4.050  
##  Median :20.30   Median : 3.400   Median : 3.400   Median :4.200  
##  Mean   :21.65   Mean   : 4.383   Mean   : 4.383   Mean   :4.304  
##  3rd Qu.:22.62   3rd Qu.: 6.200   3rd Qu.: 6.200   3rd Qu.:4.550  
##  Max.   :42.70   Max.   :10.800   Max.   :10.820   Max.   :5.700  
##     mpg_city      mpg_highway   
##  Min.   :15.00   Min.   :20.00  
##  1st Qu.:18.00   1st Qu.:26.00  
##  Median :19.00   Median :27.50  
##  Mean   :19.75   Mean   :27.50  
##  3rd Qu.:22.00   3rd Qu.:28.25  
##  Max.   :28.00   Max.   :38.00
carprice_filt_df$price %>% mean(); carprice_filt_df$price %>% median()
## [1] 19.45417
## [1] 18.25
carprice_filt_df$mpg_highway %>% mean(); carprice_filt_df$mpg_highway %>% median()
## [1] 27.5
## [1] 27.5

Exercise 5

carprice_filt_df <- carprice_filt_df %>% 
  mutate(type = as.character(type),
         type = ifelse(type=="Sporty", "sporty", 
                       ifelse(type=="Small", "small", 
                              ifelse(type=="Van", "van", type))))

Exercise 6

knitr::kable(carprice_filt_df)
id type min_price price max_price range_price rough_range gpm_100 mpg_city mpg_highway
38 Large 20.1 20.9 21.7 1.6 1.59 4.5 18 26
34 sporty 10.8 15.9 21.0 10.2 10.21 3.9 22 29
11 Midsize 37.5 40.1 42.7 5.2 5.18 4.9 16 25
17 van 14.7 16.6 18.6 3.9 3.90 5.7 15 20
25 Compact 11.9 13.3 14.7 2.8 2.81 4.1 22 27
37 Midsize 15.6 20.2 24.8 9.2 9.21 3.9 21 30
75 sporty 14.0 17.7 21.4 7.4 7.40 4.2 19 28
7 Large 19.9 20.8 21.7 1.8 1.79 4.2 19 28
27 Midsize 14.8 15.6 16.4 1.6 1.60 4.2 21 27
18 Large 18.0 18.8 19.6 1.6 1.60 4.7 17 26
70 van 19.5 19.5 19.5 0.0 0.00 4.9 18 23
24 small 8.4 11.3 14.2 5.8 5.80 3.8 23 29
33 Compact 10.4 11.3 12.2 1.8 1.82 4.1 22 27
79 small 9.2 11.1 12.9 3.7 3.70 3.0 28 38
30 Large 17.5 19.3 21.2 3.7 3.69 4.2 20 28
61 Midsize 14.9 14.9 14.9 0.0 -0.02 4.4 19 26
52 Large 34.4 36.1 37.8 3.4 3.42 4.5 18 26
71 Large 19.5 20.7 21.9 2.4 2.41 4.2 19 28
12 Compact 8.5 13.4 18.3 9.8 9.80 3.3 25 36
36 van 14.5 19.9 25.3 10.8 10.82 5.7 15 20
14 sporty 13.4 15.1 16.8 3.4 3.38 4.2 19 28
77 Large 19.4 24.4 29.4 10.0 10.00 4.2 19 28
51 Midsize 33.3 34.3 35.3 2.0 1.99 4.7 17 26
6 Midsize 14.2 15.7 17.3 3.1 3.09 3.8 22 31

Exercise 7

This was done in Step One!