Load ggplot2 library and read in data. The for loop checks to make sure that the home games and away games both sum to 41 for each team. This is because we manually collected the data, and it just a small test for errors.

set.seed(200)
library(ggplot2)

nba_data <- read.csv("/Users/Max/Desktop/nbadata.csv", row.names = 1, header = TRUE)

for (i in 1:nrow(nba_data)) {
  home = (nba_data[i,"home.wins"] + nba_data[i,"home.losses"] == 41)
  road =  (nba_data[i,"road.wins"] + nba_data[i,"road.losses"] == 41)
  if ((home & road) == F){
    print(i)
  }
}

Establish factors and show some tables to ensure the data is entered correctly.

nba_data$conference = as.factor(nba_data$conference)
nba_data$division = as.factor(nba_data$division)

table(nba_data$conference)
## 
##  eastern  western 
##       15       15
table(nba_data$division)
## 
##   atlantic    central  northwest    pacific  southeast  southwest 
##          5          5          5          5          5          5

Some histograms of the data.

hist(nba_data$home.wins)

hist(nba_data$road.wins)

ggplot(nba_data, aes(x=home.wins, fill=conference)) + geom_density(alpha=.8)

ggplot(nba_data, aes(x=road.wins, fill=conference)) + geom_density(alpha=.8)

nba_data$home.ratio = nba_data$home.wins / 41
nba_data$road.ratio = nba_data$road.wins / 41

with(nba_data, t.test(home.ratio, road.ratio, paired=TRUE))
## 
##  Paired t-test
## 
## data:  home.ratio and road.ratio
## t = 9.1434, df = 29, p-value = 4.834e-10
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  0.116132 0.183055
## sample estimates:
## mean of the differences 
##               0.1495935
nba_data
##                        conference   division home.wins home.losses
## atlanta_hawks             eastern  southeast        35           6
## cleveland_cavaliers       eastern    central        31          10
## chicago_bulls             eastern    central        27          14
## toronto_raptors           eastern   atlantic        27          14
## washington_wizards        eastern  southeast        29          12
## milwaulkee_bucks          eastern    central        23          18
## boston_celtics            eastern   atlantic        21          20
## brooklyn_nets             eastern   atlantic        19          22
## indiana_pacers            eastern    central        23          18
## miami_heat                eastern  southeast        20          21
## charlotte_hornets         eastern  southeast        19          22
## detroit_pistons           eastern    central        18          23
## orlando_magic             eastern  southeast        13          28
## philadelphia_76ers        eastern   atlantic        12          29
## new_york_knicks           eastern   atlantic        10          31
## golden_state_warriors     western    pacific        39           2
## los_angeles_clippers      western    pacific        30          11
## phoenix_suns              western    pacific        22          19
## sacramento_kings          western    pacific        18          23
## los_angeles_lakers        western    pacific        12          29
## houston_rockets           western  southwest        30          11
## memphis_grizzlies         western  southwest        31          10
## san_antonio_spurs         western  southwest        33           8
## dallas_mavericks          western  southwest        27          14
## new_orleans_pelicans      western  southwest        28          13
## portland_trail_blazers    western  northwest        32           9
## oklahoma_city_thunder     western  northwest        29          12
## utah_jazz                 western  northwest        21          20
## denver_nuggets            western  northwest        19          22
## minnesota_timberwolves    western  northwest         9          32
##                        road.wins road.losses home.ratio road.ratio
## atlanta_hawks                 25          16  0.8536585  0.6097561
## cleveland_cavaliers           22          19  0.7560976  0.5365854
## chicago_bulls                 23          18  0.6585366  0.5609756
## toronto_raptors               22          19  0.6585366  0.5365854
## washington_wizards            17          24  0.7073171  0.4146341
## milwaulkee_bucks              18          23  0.5609756  0.4390244
## boston_celtics                19          22  0.5121951  0.4634146
## brooklyn_nets                 19          22  0.4634146  0.4634146
## indiana_pacers                15          26  0.5609756  0.3658537
## miami_heat                    17          24  0.4878049  0.4146341
## charlotte_hornets             14          27  0.4634146  0.3414634
## detroit_pistons               14          27  0.4390244  0.3414634
## orlando_magic                 12          29  0.3170732  0.2926829
## philadelphia_76ers             6          35  0.2926829  0.1463415
## new_york_knicks                7          34  0.2439024  0.1707317
## golden_state_warriors         28          13  0.9512195  0.6829268
## los_angeles_clippers          26          15  0.7317073  0.6341463
## phoenix_suns                  17          24  0.5365854  0.4146341
## sacramento_kings              11          30  0.4390244  0.2682927
## los_angeles_lakers             9          32  0.2926829  0.2195122
## houston_rockets               26          15  0.7317073  0.6341463
## memphis_grizzlies             24          17  0.7560976  0.5853659
## san_antonio_spurs             22          19  0.8048780  0.5365854
## dallas_mavericks              23          18  0.6585366  0.5609756
## new_orleans_pelicans          17          24  0.6829268  0.4146341
## portland_trail_blazers        19          22  0.7804878  0.4634146
## oklahoma_city_thunder         16          25  0.7073171  0.3902439
## utah_jazz                     17          24  0.5121951  0.4146341
## denver_nuggets                11          30  0.4634146  0.2682927
## minnesota_timberwolves         7          34  0.2195122  0.1707317