The impact of hiring new graduates

2020, 2021, we did not hire new graduates.
2022, we hired new graduates.

I would like to have some analysis done to show the impact on the month/Qtr. when we hired new graduate nurses vs. all other months/quarters when we did not hire new graduate nurses.

We hired new graduate nurses Quarter 1, 2022/ month of February 2022.
All other quarters and months, we did not hire new graduates.

Also I have data on the vacancy rates per quarter. Id like analysis correlating the hiring rates with the vacancy rates.

Hypothesis:
Hiring new graduates in the ED increase hiring rates
Hiring new graduates in the ED have no effect on hiring rates

Hiring new graduates in the ED improves vacancy rates
Hiring new graduates in the ED does not improve vacancy rates

Lastly want a qualitative analysis completed.