Was the streak plate method effective at diluting the population size in all 4 plates?

"Yes" The streak plate method is very effective in diluting the population size in all 4 plates.

Explanation:

The streak plate method is effective because it is one among the rapid isolation method which further allows for easy observation of the bacteria. This method is also being used for getting the color of the certain substances. Its main principle is to isolate the specific bacteria from the sample of various microbes. It dilutes the microbes number and often reduces their density. It is useful in separation of organisms from the group. These are isolated in the agar plate.