1. T-test of average monthly hours by Left

1. Correlation

## 
##  Welch Two Sample t-test
## 
## data:  hr$average_montly_hours by hr$left
## t = -7.5323, df = 4875.1, p-value = 5.907e-14
## alternative hypothesis: true difference in means between group 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  -10.534631  -6.183384
## sample estimates:
## mean in group 0 mean in group 1 
##        199.0602        207.4192

2. Technical interpretation

We reject the (H0), p-value < 0.01 and conclude that there is a difference in average monthly hours between employees that stayed vs left.

3. Non-technical interpretation

Employees that worked more hours left.

4. Graph

2. T-test of satisfaction level by Left

1. Correlation

## 
##  Welch Two Sample t-test
## 
## data:  hr$satisfaction_level by hr$left
## t = 46.636, df = 5167, p-value < 2.2e-16
## alternative hypothesis: true difference in means between group stayed and group left is not equal to 0
## 95 percent confidence interval:
##  0.2171815 0.2362417
## sample estimates:
## mean in group stayed   mean in group left 
##            0.6668096            0.4400980

2. Technical interpretation

We reject the (H0), p-value < 0.01 and conclude that there is a difference in satisfaction level between employees that stayed vs left.

3. Non-technical interpretation

Employees that left had lower satisfaction levels.

4. Graph

3. T-test of Number of Projects by Left

1. Correlation

## 
##  Welch Two Sample t-test
## 
## data:  hr$number_project by hr$left
## t = -2.1663, df = 4236.5, p-value = 0.03034
## alternative hypothesis: true difference in means between group stayed and group left is not equal to 0
## 95 percent confidence interval:
##  -0.131136535 -0.006540119
## sample estimates:
## mean in group stayed   mean in group left 
##             3.786664             3.855503

2. Technical interpretation

We fail to reject the (H0), p-value > 0.01 and conclude that there is not a difference in number of projects between employees that stayed vs left

3. Non-technical interpretation

All employees had similar number of projects with employees who left having slightly more projects.

4. Graph

4. T-test of Time Spent at Company by Left

1. Correlation

## 
##  Welch Two Sample t-test
## 
## data:  hr$time_spend_company by hr$left
## t = -22.631, df = 9625.6, p-value < 2.2e-16
## alternative hypothesis: true difference in means between group stayed and group left is not equal to 0
## 95 percent confidence interval:
##  -0.5394767 -0.4534706
## sample estimates:
## mean in group stayed   mean in group left 
##             3.380032             3.876505

2. Technical interpretation

We reject the (H0), p-value < 0.01 and conclude that there is a difference in time spent at the company between employees that stayed vs left

3. Non-technical interpretation

Employees who left spent more time at the company than those who stayed.

4. Graph