Load the data

T-Test 1

## 
##  Welch Two Sample t-test
## 
## data:  satisfaction_level by 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

Technical Interpretation 1

Since p < 0.01, the difference is statistically significant. Employees who left were significantly less satisfied than those who stayed.

Non-Technical Interpretation 1

The more satisfied, the more likely an employee will stay.

Plot 1

T- Test 2

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

Technical Interpretation 2

Since p > 0.01, the difference is not statistically significant. There is no strong evidence that last evaluation scores differ between those who stayed and left.

Non-Technical Interpretation 2

Performance evaluations do not seem to impact whether an employee stays or leaves. Employees who quit had similar evaluations to those who remained. ## Plot 2 ## T-Test 3

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

Technical Interpretation 3

Since p < 0.01, employees who left clearly worked more hours each month than those who stayed, suggesting heavier workloads may drive turnover.

Non-Technical Interpretation 3

People who worked more hours were more likely to quit.

Plot 3

T-test 4

## 
##  Welch Two Sample t-test
## 
## data:  time_spend_company by 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

##Technical Interpretation 4 Since p < 0.01, this is real: employees who left had been at the company for longer than those who stayed.

Non-Technical Interpreation 4

People who quit had been at the company longer.

Plot 4