PARTS A) and B) are unrelated. All are compulsory.

PART A: A researcher wants to estimate the mean time (hours) a person speaks on a mobile phone, per day. They took a random sample of 36 mobile phone users and found a sample mean time of 2.8 hours. Assume the population standard deviation is known to be 0.5 hours. Do NOT check conditions.

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

ii)Interpret your confidence interval.

PART B: If p= 0.5 and p = 0.3, and n = 30, find the corresponding Z value using the relevant formula.