Elementary Statistics Question 3 Do ringing cell phones disturb business presentations? In a poll with 1500 participants, 975 answered this question with "yes" and the other 525 answered this question with "no". (a) Construct a 95% confidence interval for the population proportion of people would have their business presentations disturbed by ringing cell phones. (8 marks) (b) What is the effect to the width of the confidence interval if the confidence interval is constructed at 98% confidence level for the same sample? (no calculation is required for part (b)) (Answer: wider / narrower / no change) (2 marks) (Total: 10 marks)