Hypothesis Testing for Proportions

Slides:



Advertisements
Similar presentations
Hypothesis Testing For Proportions
Advertisements

7 Chapter Hypothesis Testing with One Sample
Testing a Claim about a Proportion Assumptions 1.The sample was a simple random sample 2.The conditions for a binomial distribution are satisfied 3.Both.
Hypothesis Testing A hypothesis is a claim or statement about a property of a population (in our case, about the mean or a proportion of the population)
7.4 Hypothesis Testing for Proportions
Copyright © 2014, 2013, 2010 and 2007 Pearson Education, Inc. Chapter Hypothesis Tests Regarding a Parameter 10.
Section 7-2 Hypothesis Testing for the Mean (n  30)
Significance Tests for Proportions Presentation 9.2.
Hypothesis Testing with One Sample
Hypothesis Testing for Proportions 1 Section 7.4.
The Probability of a Type II Error and the Power of the Test
Hypothesis Testing with One Sample Chapter 7. § 7.1 Introduction to Hypothesis Testing.
Hypothesis Testing for Proportions
Section 9.3 ~ Hypothesis Tests for Population Proportions Introduction to Probability and Statistics Ms. Young.
Hypothesis Testing for the Mean (Small Samples)
HAWKES LEARNING SYSTEMS Students Matter. Success Counts. Copyright © 2013 by Hawkes Learning Systems/Quant Systems, Inc. All rights reserved. Example 10.17:
Welcome to MM207 – Statistics Hypothesis Testing with One Sample Chapter – 7.4 Anthony J. Feduccia.
Slide Slide 1 Copyright © 2007 Pearson Education, Inc Publishing as Pearson Addison-Wesley. Overview.
Hypothesis Testing with One Sample Chapter 7. § 7.1 Introduction to Hypothesis Testing.
Slide Slide 1 Section 8-4 Testing a Claim About a Mean:  Known.
Logic and Vocabulary of Hypothesis Tests Chapter 13.
Inference with Proportions Review Mr. Hardin AP STATS 2015.
Statistical Inference Drawing conclusions (“to infer”) about a population based upon data from a sample. Drawing conclusions (“to infer”) about a population.
Introduction to Hypothesis Testing
Created by Erin Hodgess, Houston, Texas Section 7-1 & 7-2 Overview and Basics of Hypothesis Testing.
Level of Significance Level of significance Your maximum allowable probability of making a type I error. – Denoted by , the lowercase Greek letter alpha.
Step by Step Example of Hypothesis Testing of a Proportion.
Section 7.4 Hypothesis Testing for Proportions © 2012 Pearson Education, Inc. All rights reserved. 1 of 101.
Section 7.4 Hypothesis Testing for Proportions © 2012 Pearson Education, Inc. All rights reserved. 1 of 14.
SWBAT: -Determine whether to use a one or two tailed test and calculate the necessary p-value -Make and interpret a decision based on the results of a.
Chapter Hypothesis Testing with One Sample 1 of 35 7  2012 Pearson Education, Inc. All rights reserved.
7 Chapter Hypothesis Testing with One Sample
Hypothesis Testing with One Sample
Hypothesis Testing: One-Sample Inference
Section 8.2 Day 3.
9.3 Hypothesis Tests for Population Proportions
Chapter 7 Hypothesis Testing with One Sample.
Chapter 7 Hypothesis Testing with One Sample.
STA 291 Spring 2010 Lecture 18 Dustin Lueker.
Chapters 20, 21 Hypothesis Testing-- Determining if a Result is Different from Expected.
Hypothesis Testing for Proportions
Section 8.2 Day 4.
Hypothesis Tests for 1-Sample Proportion
Testing a Claim About a Mean:  Known
Elementary Statistics: Picturing The World
Week 11 Chapter 17. Testing Hypotheses about Proportions
Chapter 7 Hypothesis Testing with One Sample.
Elementary Statistics: Picturing The World
Hypothesis Testing (Cont.)
Elementary Statistics
Section 7-4 Hypothesis Test for Proportions
P-values P-value (or probability value)
Hypothesis Tests for Proportions
Tests About a Population Proportion
CHAPTER 12 Inference for Proportions
STA 291 Spring 2008 Lecture 18 Dustin Lueker.
Introduction to Hypothesis Testing
Power Section 9.7.
CHAPTER 12 Inference for Proportions
More on Testing 500 randomly selected U.S. adults were asked the question: “Would you be willing to pay much higher taxes in order to protect the environment?”
Comparing Two Proportions
Hypothesis Testing for Proportions
STA 291 Summer 2008 Lecture 18 Dustin Lueker.
Comparing Two Proportions
Comparing Two Proportions
Testing Hypotheses about a Population Proportion
Section 11.1: Significance Tests: Basics
Hypothesis Testing for Proportions
Testing Hypotheses about a Population Proportion
Testing a Claim About a Mean:  Known
Presentation transcript:

Hypothesis Testing for Proportions Essential Statistics

Hypothesis Test for Proportions In this section, you will learn how to test a population proportion, p. If np ≥ 10 and n(1-p) ≥ 10 for a binomial distribution, then the sampling distribution for is normal with and

Steps for doing a hypothesis test “Since the p-value < (>) a, I reject (fail to reject) the H0. There is (is not) sufficient evidence to suggest that Ha (in context).” Assumptions Write hypotheses & define parameter Calculate the test statistic & p-value Write a statement in the context of the problem.  

What is the p-value The P-Value is the probability of obtaining a test statistic that is at least as extreme as the one that was actually observed, assuming the null is true. p-value < (>) a, I reject (fail to reject) the H0.

How to calculate the P-value Under Stat – Tests Select 1 Prop Z-test Input p, x, and n P is claim proportion X is number of sampling matching claim N is number sampled Select correct Alternate Hypothesis Calculate

Reading the Information Provides you with the z score P-Value Sample proportion Interpret the p-value based off of your Confidence interval

Draw & shade a curve & calculate the p-value: 1) right-tail test z = 1.6 2) two-tail test z = 2.3 P-value = .0548 P-value = (.0107)2 = .0214

What is a a Represents the remaining percentage of our confidence interval. 95% confidence interval has a 5% alpha.

Ex. 1: Hypothesis Test for a Proportion A medical researcher claims that less than 20% of American adults are allergic to a medication. In a random sample of 100 adults, 15% say they have such an allergy. Test the researcher’s claim at  = 0.01.

SOLUTION The products np = 100(0.20)= 20 and nq = 100(0.80) = 80 are both greater than 10. So, you can use the z-test. The claim is “less than 20% are allergic to a medication.” So the null and alternative hypothesis are: Ho: p = 0.2 and Ha: p < 0.2 (Claim)

Solution By HAND continued . . . Because the test is a left-tailed test and the level of significance is  = 0.01, the critical value is zo = -2.33 and the rejection region is z < -2.33. Using the z-test, the standardized test statistic is:

SOLUTION Continued . . . The graph shows the location of the rejection region and the standardized test statistic, z. Because z is not in the rejection region, you should decide not to reject the null hypothesis. In other words, there is not enough evidence to support the claim that less than 20% of Americans are allergic to the medication.

Solutions Continued……  

Interpretation Since the .1056 > .01, I fail to reject the H0 There is not sufficient evidence to suggest that 20% of adults are allergic to medication.

Ex. 2 Hypothesis Test for a Proportion Harper’s Index claims that 23% of Americans are in favor of outlawing cigarettes. You decide to test this claim and ask a random sample of 200 Americas whether they are in favor outlawing cigarettes. Of the 200 Americans, 27% are in favor. At  = 0.05, is there enough evidence to reject the claim?

SOLUTION: The products np = 200(0.23) = 45 and nq = 200(0.77) = 154 are both greater than 5. So you can use a z-test. The claim is “23% of Americans are in favor of outlawing cigarettes.” So, the null and alternative hypotheses are: Ho: p = 0.23 (Claim) and Ha: p  0.23

SOLUTION continued . . . Because the test is a two-tailed test, and the level of significance is  = 0.05. Z = 1.344 P = .179 Since the .179 > .05, I fail to reject the H0 There is not sufficient evidence to suggest that more or less than 23% of Americans are in favor of outlawing cigarette’s.

SOLUTION Continued . . . The graph shows the location of the rejection regions and the standardized test statistic, z. Because z is not in the rejection region, you should fail to reject the null hypothesis. At the 5% level of significance, there is not enough evidence to reject the claim that 23% of Americans are in favor of outlawing cigarettes.

Ex. 3 Hypothesis Test a Proportion The Pew Research Center claims that more than 55% of American adults regularly watch a network news broadcast. You decide to test this claim and ask a random sample of 425 Americans whether they regularly watch a network news broadcast. Of the 425 Americans, 255 responded yes. At  = 0.05, is there enough evidence to support the claim?

SOLUTION: The products np = 425(0.55) = 235 and nq = 425(0.45) = 191 are both greater than 5. So you can use a z-test. The claim is “more than 55% of Americans watch a network news broadcast.” So, the null and alternative hypotheses are: Ho: p = 0.55 and Ha: p > 0.55 (Claim)

SOLUTION continued . . . Because the test is a right-tailed test, and the level of significance is  = 0.05. Z = 2.072 P-value = .019 Since the 0.019 < .05, I reject the H0. There is sufficient evidence to suggest that 20% of adults are allergic to medication.

SOLUTION Continued . . . The graph shows the location of the rejection region and the standardized test statistic, z. Because z is in the rejection region, you should decide to There is enough evidence at the 5% level of significance, to support the claim that 55% of American adults regularly watch a network news broadcast.