STT 200 – L ECTURE 1, SECTION 2,4 R ECITATION 13 (11/27/2012) TA: Zhen (Alan) Zhang Office hour: (C500 WH) 1:45 – 2:45PM Tuesday (office tel.: ) Help-room: (A102 WH) 11:20AM-12:30PM, Monday, Friday Class meet on Tuesday: 3:00 – 3:50PM A122 WH, Section 02 12:40 – 1:30PM A322 WH, Section 04 1

O VERVIEW We will discuss following problems:  Chapter 19 “Confidence Intervals for Proportions” (Page 504) Nos. 7, 8, 14, 22, 27, 28 All recitation PowerPoint slides available at herehere 2

3

Review (cont’d) Margin of error 4

5

Chapter 19 (Page 504): #7: Which statements are true? a) For a given sample size, higher confidence means a smaller margin of error. b) For a specified confidence level, larger samples provides smaller margins of error. c) For a fixed margin of error, larger samples provide greater confidence. d) For a given confidence level, halving the margin of error requires a sample twice as large. 6

Chapter 19 (Page 504): #8: Which statements are true? a) For a given sample size, reducing the margin of error will mean lower confidence. b) For a certain confidence level, you can get a smaller margin of error by selecting a bigger sample. c) For a fixed margin of error, smaller samples will mean lower confidence. d) For a given confidence level, a sample 9 times as large will make a margin of error one third as big. 7

8

9

10

11

12

Thank you. 13