Answer:
a) Increase the sample size
Step-by-step explanation:
Given that a 95% confidence interval for μ turns out to be (1,000, 2,100)
The confidence interval is formed as
Margin of error = critical value * std dev/sqrt of sample size
Hence for the same confidence level, we cannot change critical value.
The only available ways are either to decrease std deviation or increase the sample size to make it narrower.
If confidence level becomes higher, then confidence interval would be wider.
Here out of four options the correct option is
a) Increase the sample size