Chapter 10 Lecture Outline

Chapter 10 Lecture Outline - CHAPTER 10 Estimating...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
CHAPTER 10 Estimating Proportions with Confidence Review of Ch 9 information we will use in Ch 10: One Proportion – one categorical variable If np and n(1-p) are both greater than or equal to 10, then the distribution of p ˆ ’s can be described as: the shape is approximately normal the mean is p the standard deviation is n p p ) 1 ( - the standard error is n p p ) ˆ 1 ( ˆ - Two Proportions – two categorical variables If n 1 p 1 ,n 1 (1-p 1 ), n 2 p 2 and n 2 (1-p 2 ) are all greater than or equal to 10, then the distribution of 2 1 ˆ ˆ p p - ’s can be described as: the shape is approximately normal the mean is p 1 -p 2
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
the standard deviation is 2 2 2 1 1 1 ) 1 ( ) 1 ( n p p n p p - + - the standard error is 2 2 2 1 1 1 ) ˆ 1 ( ˆ ) ˆ 1 ( ˆ n p p n p p - + - Multiplier values: We can use the z- table in reverse (similar to percentiles) to get common z* multipliers for CI’s about proportions. CI level: Look for this probability: z*: 80 90 95 98 99 As the sample size increases the standard error will decrease and the confidence interval gets smaller. So a larger sample size gives us a more precise estimate of our parameter. As the confidence level increases, the multiplier increases leading to a wider confidence interval. Confidence intervals have the general form: Sample estimate ± Margin of error OR Sample estimate ± Multiplier * Standard Error
Background image of page 2
Interpretation: We are _____% confident that the true (population parameter) of <variable> is between _____ and _____. For two proportions, indicate which proportion is higher or lower
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

Chapter 10 Lecture Outline - CHAPTER 10 Estimating...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online