Consider the 100(1 - )% confidence interval for the population proportionpbased on a random sample of sizenwith a sample proportionp.Which of the following would cause the confidence interval to becomenarrower?Consider each statement separately.

(Note: You may assume the sample size to be sufficiently large so that the sample size assumption is satisfied.)

1. Increasing the confidence level from 90% to 95%, while everything else remains unchanged.
2. Increasingp from 0.4 to 0.8, while everything else remains unchanged.
3. Increasing the sample sizenfrom 100 to 200, while everything else remains unchanged.

a) i. only

b)ii. and iii.

c) i, ii, and iii

d) iii only