Answer:
Keep the line operating as it is inside the confidence interval
Step-by-step explanation:
A confidence interval of a proportion p% at the x% level with m% margin of error means that:
We are x% sure that the true mean of the population is in the interval from (p-x)% to (p+x)%.
In this problem, we have that:
The 95% confidence interval for these parts is 56.98 to 57.05 under normal operations. This means that we are 95% that these parts are between 56.98 and 57.05.
The mean of the sample is 56.99. This is inside the confidence interval.
The correct answer is:
Keep the line operating as it is inside the confidence interval