If all other quantities remain the same, how does the indicated change affect the width of a confidence interval? (a) Increase in the level of confidence (b) Increase in the sample size (c) Increase in the population standard deviation *** (a) How does an increase in the level of confidence affect the width of a confidence interval? Choose the correct answer below. An increase in the level of confidence the confidence interval. (b) How does an increase in the sample size affect the width of a confidence interval? Choose the correct answer below. An increase in the sample size the confidence interval. (c) How does an increase in the population standard deviation affect the width of a confidence interval? Choose the correct answer below. An increase in the population standard deviation the confidence interval.