1. ECON103 Week 19 Rob Pryce www.robpryce.co.uk/teaching

2. PE7.2 Q3

3. PE 7.2 Q5

4. Standard error Margin of error

5. Your Turn - PE7.3 Q7 7. An opinion poll of 410 voters taken a week before an election showed that 138 intended to vote for the current party in power (referred to as Party A), 102 for the largest opposition party (Party B), 67 for others, 82 don’t know, 21 won’t vote at all. (a)Calculate a 95% confidence interval for the proportion that will vote for the current party in power. What is the margin of error for this estimate? Is this party likely to gain more than 50% of the vote? (b)Calculate a 95% confidence interval for the proportion that will vote for the main opposition party.

6. PE7.4 Q5 5. A survey of regular customers in (i) restaurants and (ii) pubs were asked whether they approve of non-smoking in their restaurant/pub. Their responses are given below: Restaurant customersPub customers Approve6436 Total surveyed11272

7. PE7.4 Q5 Restaurant customersPub customers Approve6436 Total surveyed11272

8. Your Turn - PE7.4 Q7 In a dental practice the number of patients who do not show up for appointments is thought to be particularly high on Mondays. Form past records, the number of ‘no shows’ on randomly selected Mondays and Tuesdays are as follows: MondayTuesday Number of appointments248240 Number of ‘no shows’5231 Calculate a 98% confidence interval for the difference in the proportion of ‘no shows’ between Mondays and Tuesdays. Interpret your results.

9. Questions? Email:r.pryce Web:www.robpryce.co.uk/teachingwww.robpryce.co.uk/teaching Office Hour:By appointment