3pt b) Suggest one way that is always under the control of the researcher of making the margin of error smaller.

By making use of a lower confidence level

Step-by-step explanation:

The margin of error is also referred to as the confidence interval and it is the system in which we use to measure the error in the result of the survey or experiment.

Now, for us to reduce the margin of error, there are different things we can do such as;

- increasing sample size

- using less data variation

- making use of a lower confidence level

- making use of a one sided confidence interval rather than a two sided confidence interval.

Looking at the above different methods of making the margin of error smaller, the one that is always under the control of the researcher is "making use of a lower confidence level".

Every other means, he does not have as much control as he has to do to lower the confidence level. That one is strictly based on his jurisdiction.