1. t-test of average monthly hours by Left

t-test

## 
##  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

Technical Interpretation

Rejecting the null h0, p-value was less than 0.01, where the satisfaction levels for

employees that left is greater

Non-Technical Interpretation

Employees with less satisfaction levels are more likely to leave

Graph

2. t-test of Satisfaction level by Left

t-test

## 
##  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 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  0.2171815 0.2362417
## sample estimates:
## mean in group 0 mean in group 1 
##       0.6668096       0.4400980

Technical Interpretation

Rejecting the null h0, p-value was less than 0.01, where the satisfaction levels for

employees that left is greater

Non-Technical Interpretation

Less Satisfied Employees are more likely to leave

Graph

3. t-test of Evaluation Score by Left

t-test

## 
##  Welch Two Sample t-test
## 
## data:  hr$last_evaluation by hr$left
## t = -0.72534, df = 5154.9, p-value = 0.4683
## alternative hypothesis: true difference in means between group 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  -0.009772224  0.004493874
## sample estimates:
## mean in group 0 mean in group 1 
##       0.7154734       0.7181126

Technical Interpretation

Accepting the null h0, p-value was greater than 0.01, where the evaluation score

is around the same

Non-Technical Interpretation

Employees with lower evaluation scores are not more likely to leave

Graph

4. t-test of Time Spent in company by Left

t-test

## 
##  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 0 and group 1 is not equal to 0
## 95 percent confidence interval:
##  -0.5394767 -0.4534706
## sample estimates:
## mean in group 0 mean in group 1 
##        3.380032        3.876505

Technical Interpretation

Rejecting the null h0, p-value was less than 0.01, where the time spent in the company

for employees that left is less

Non-Technical Interpretation

Employees with more time spent in the company are slightly more likely to leave

Graph