Have I Grasped the Key Concepts Here?

A study has been conducted to examine the impact of comprehensive smoking ban on AMI mortality rate and results are summarized in the table below (Note RR is calculated using before ban as the reference):

Based on above table, answer the following questions:

The following questions are based on this situation: You work with the City of Milwaukee Health Department. Recently, a large outbreak of Cryptosporidiosis has occurred, affecting tens of thousands of people. The following two videos describe some basic information on Cryptospordiosis and Cryptosporidium (Note you can select full screen if you want):

You suspect that the drinking water supply may be the cause.You randomly selected 30 residents and questioned them as to whether they have the symptoms of cryptosporidiosis and whether they drink the city water. Your results are summarized in the Table below.

Based on the table above, please answer the following questions (note, we will use group without city water consumption as the reference group in RR and AR calculation).