Parts a) and b) are unrelated. All are compulsory.

PART A: A researcher wanted to estimate the mean time (minutes) a person uses their mobile phone, for social media, per day. They took a random sample of 16 mobile phone users and found a sample mean time of 58 minutes. Assume the population standard deviation is known to be 5 minutes. Do NOT check conditions.

i)Construct a 95% confidence interval. SHOW BASIC WORKINGS.

ii)Interpret your confidence interval.

PART B: If p'sample proportion'= 0.8 and p = 0.6, and n = 50, find the corresponding Z value using the relevant formula