Homework 8 & 9

Part 2:
Null hypothesis: Our company's monthly income is not significantly different from the national average.
Alt hypothesis: Our company's monthly income is significantly different from the national average.

Mean: $5,099.20

P-value: 0

Reject the null hypothesis as our mean monthly income is much lower than $6,200

Part 3:
Null hypothesis: Our company's turnover rate is not significantly different from the industry baseline.
Alt hypothesis: Our company's turnover rate is significantly different from the industry baseline.

Mean: .057

P-value: 0

Reject the null hypothesis as our mean turnover rate is higher than the significance level.

The HR director should not be worried as the number is close.

Part 4:
Null hypothesis: Attrition is independent of the department.
Alt hypothesis: Attrition is dependent on the department.

Research and development

Chi-squared test statistic: 3,079.1052
degrees of freedom: 2
exact p-value: 0

Reject the null hypothesis as our p-value is lower than the significance level.

The attrition rate is dependent on the department.