BUS310_L20_3.31.11 - Inferential Statistics / Simple...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

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

View Full DocumentRight Arrow Icon
Lecture 20: Inferential Statistics / Simple Regression Chapter 12 (12.1, 2) 22
Background image of page 2
Review Handout Chapters 9, 10, 11 PS5 PS6 New Material: Simple Linear Regression (Chapter 12 – next 3 lectures) How to use regression analysis to predict the value of a dependent variable based on an independent variable (e.g., sales, based on store size) 33
Background image of page 3

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

View Full DocumentRight Arrow Icon
PS5 44
Background image of page 4
PS5 (Chapter 9) 1. Problem 9.67 (2 points) An audit was conducted on a sample of 75 reimbursements by Medicare to physicians , with the following results: -. The average amount of reimbursement was X = $93.70, (SD=$34.55) . -. In 12 of the 75 office visits , an incorrect reimbursement amount was provided. a) At the 0.05 level of significance, is there evidence that the population mean reimbursement was less than $100 ? d) What is your answer to a) if the sample mean equals $90 ? c) Discuss the underlying assumptions .
Background image of page 5

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

View Full DocumentRight Arrow Icon
P-value: 0.059284 We are 94.07% confident that the average amount of all Medicare reimbursements is less than $100. There is not enough evidence to reject H0 (the mean of all reimbursements is equal or greater than $100.) Hypotheses: H1: μ < 100 H0: μ ≥ 100 a) At the 0.05 level of significance, is there evidence that the population mean reimbursement was less than $100 ?
Background image of page 6
d) What is your answer to a) if the sample mean equals $90 ? Hypotheses: H1: μ < 100 H0: μ ≥ 100 Now the sample mean is lower, which should increase our confidence that the population mean is below $100. P-value: 0.00719 & Actual Confidence (1 - P-value) = 99.28% Now we are more than 99% confident that the average reimbursement amount from Medicare is less than $100. Reject H0 .
Background image of page 7

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

View Full DocumentRight Arrow Icon
c) Discuss the underlying assumptions for the test in a). We have to check the assumption of Normality to determine whether the test is valid. The assumption of normality is met, because the sample size is large (greater than 30) with n = 75).
Background image of page 8
Sample proportion is 16% (=12/75) Based on these data, how confident are you that the population proportion is greater than 10%? Hypotheses: H1: π > 0.1 H0: π ≤ 0.1 P-value: 0.0416 Actual Confidence (1 - P-value) = 95.84% We are 95.8% confident that the proportion of incorrect reimbursements from Medicare (of all reimbursements) is greater than 0.10 (10%). Reject the Null Hypothesis. b) At the 0.05 level of significance, is there evidence that the proportion of incorrect reimbursements in the population was greater than 0.10 ?
Background image of page 9

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

View Full DocumentRight Arrow Icon
(=15/75). Our confidence should increase, that the population proportion is higher than 10%. H1: π > 0.1 H0: π ≤ 0.1 P-value: 0.00195 Actual Confidence (1 - P-value) = 0.99805 = 99.81% We are 99.8% confident that the proportion of incorrect reimbursements in the population was greater than 0.10. Reje
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/08/2011 for the course BUS 310 taught by Professor Abou-sayf,f during the Spring '08 term at University of Hawaii, Manoa.

Page1 / 34

BUS310_L20_3.31.11 - Inferential Statistics / Simple...

This preview shows document pages 1 - 11. Sign up to view the full document.

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