A study is conducted concerning the blood pressure of 60 year old women with glaucoma. In the study, 200 of 60 year-old women with glaucoma are randomly selected. The sample mean of systolic blood pressure is 140 mm Hg and the sample standard deviation is 25 mm Hg.

i. Calculate a 95% confidence interval for the true mean of systolic blood pressure among the population of 60 year old women with glaucoma.

ii. Suppose the study above was based on 100 women instead of 200, and the sample mean (140) and standard deviation (25) are the same. Recalculate the 95% confidence interval. Does the interval get wider or narrower?