Lab on microbes in the environment

1)  The effectiveness of sanitation procedures in hospitals is determined by sampling surface for bacteria. Samples can be taken by rubbing a sterile, moistened  cotton swab on a surface and inoculating a nutrient agar plate or with a Rodac environmental sampling plate. The 67-mm plates are designed so that an agar medium can be overfilled, producing a dome-shaped surface that ca be pressed onto a surface for sampling microbes. As the sanitation control officer, you test each method to determine which you will see. What can you conclude from these results?
   Number of plates with colonies   Number of plates inoculated
Swab onto nutrient agar   5   50
Rodac plate containing nutrient agar   6   40