Question 1: Satisfaction Level by Attrition
##
## 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
Interpretations:
P-Value Interpretation: The p-value is < 2.2e-16, which is
extremely small, indicating a statistically significant difference; we
reject the null hypothesis.
T-Test Interpretation: The mean satisfaction level for employees who
stayed is 0.67, while for those who left, it is 0.44. This significant
difference suggests that lower satisfaction is associated with higher
attrition.
Non-Technical Interpretation: Employees who left the company had
significantly lower satisfaction levels than those who stayed.
Question 2: Last Evaluation Score by Attrition
##
## 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
Interpretations:
P-value Interpretation: The p-value is 0.4683, which is much greater
than 0.01. This indicates that the difference in last evaluation scores
between employees who left and those who stayed is not statistically
significant; we fail to reject the null hypothesis.
T-test Interpretation: The mean last evaluation score for employees
who stayed is 0.715, while for those who left, it is 0.718. Since the
p-value is high, we do not have enough evidence to conclude that there
is a meaningful difference in last evaluation scores between the two
groups.
Non-technical Interpretation: Employees who left and those who
stayed had similar last evaluation scores, meaning performance
evaluations do not appear to be a factor in whether an employee left or
stayed.
Question 3: Average Monthly Hours by Attrition
##
## 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
Interpretations:
P-value Interpretation: The p-value is 5.907e-14, which is extremely
small (<0.01), confirming a significant difference; we reject the
null hypothesis.
T-test Interpretation: The mean monthly working hours for employees
who stayed is 199.06, while for those who left, it is 207.42. This
indicates that employees who worked longer hours were more likely to
leave the company.
Non-technical Interpretation: Employees who worked longer hours per
month were more likely to leave the company.
Question 4: Time Spent at Company by Attrition
##
## 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
Interpretations:
P-Value Interpretation: The p-value is < 2.2e-16, which is
extremely small, confirming a significant difference; we reject the null
hypothesis.
T-test Interpretation: The mean time spent at the company for
employees who stayed is 3.38 years, while for those who left, it is 3.88
years. This indicates that employees who had been at the company longer
were more likely to leave.
Non-technical Interpretation: Employees who had been at the company
for more years were more likely to leave.