Answer:
The best recommendation is to: Increase the sample size.
Step-by-step explanation:
The width of a confidence interval ,depends on three things,
- Sample size (n)
- Standard deviation
- Confidence level
To decrease the width the following options can be used:
- Increase the sample size.
Since the sample is inversely proportional to the width of the confidence interval, increasing the value of <em>n</em> will decrease the width.
- Decrease the standard deviation.
The standard deviation is directly proportional to the width of the confidence interval. On decreasing the standard deviation value the width of the interval will also decrease.
- Decrease the confidence level.
The critical value of the distribution is based on the confidence level. Higher the confidence level, higher will be critical value.
So, on deceasing the confidence level the critical value will decrease, hence decreasing the width of the interval.
Thus, the best recommendation is to: Increase the sample size.