Mixed Examples of Hypothesis Testing & Confidence Intervals

Slides:

Advertisements

Similar presentations

Do Now Do you have extra credit to turn in? Get out pink review paper.

Advertisements

Chapter 10, part D. IV. Inferences about differences between two population proportions You will have two population proportions, p1 and p2. The true.

Active Learning Lecture Slides For use with Classroom Response Systems Statistical Inference: Significance Tests about Hypotheses.

Active Learning Lecture Slides For use with Classroom Response Systems Statistical Inference: Significance Tests about Hypotheses.

Inference for Two Proportions Chapter 22

POLS 7000X STATISTICS IN POLITICAL SCIENCE CLASS 7 BROOKLYN COLLEGE-CUNY SHANG E. HA Leon-Guerrero and Frankfort-Nachmias, Essentials of Statistics for.

Introduction to Linear Regression and Correlation Analysis

Experimental Statistics - week 2

Inference about Two Population Proportions. Definition A sampling method is independent when the individuals selected for one sample do not dictate which.

An importer of Herbs and Spices claims that average weight of packets of Saffron is 20 grams. However packets are actually filled to an average weight,

Lecture 14 Testing a Hypothesis about Two Independent Means.

Sullivan – Fundamentals of Statistics – 2 nd Edition – Chapter 11 Section 2 – Slide 1 of 25 Chapter 11 Section 2 Inference about Two Means: Independent.

1 Level of Significance α is a predetermined value by convention usually 0.05 α = 0.05 corresponds to the 95% confidence level We are accepting the risk.

What do Centurions think about our school spirit? Diana Tapia Period

Review from before Christmas Break. Sampling Distributions Properties of a sampling distribution of means:

Lesson Testing Claims about a Population Mean Assuming the Population Standard Deviation is Known.

The Practice of Statistics Third Edition Chapter 10: Estimating with Confidence Copyright © 2008 by W. H. Freeman & Company Daniel S. Yates.

Confidence Intervals and Tests of Proportions. Assumptions for inference when using sample proportions: We will develop a short list of assumptions for.

Significance Test A claim is made. Is the claim true? Is the claim false?

Introduction to Inferece BPS chapter 14 © 2010 W.H. Freeman and Company.

The z test statistic & two-sided tests Section

Example Suppose we want to prove that the mean commute time for people in Lexington to get to work is less than 20 minutes. A random sample of 125 people.

: An alternative representation of level of significance. - normal distribution applies. - α level of significance (e.g. 5% in two tails) determines the.

Exam 2 Review. Example Information A researcher wants to know if using their flashcard program increases the number of items an individual can memorize.

Inferences Concerning Variances

Lesson Use and Abuse of Tests. Knowledge Objectives Distinguish between statistical significance and practical importance Identify the advantages.

HYPOTHESIS TESTING `. Statistical Inference the methods for drawing a conclusion about the population we have sampled, while at the same time having some.

A random sample of 42 textbooks has a mean price of $114

Comparing Two Proportions. AP Statistics Chap 13-2 Two Population Proportions The point estimate for the difference is p 1 – p 2 Population proportions.

Warm Up In May 2006, the Gallup Poll asked 510 randomly sampled adults the question “Generally speaking, do you believe the death penalty is applied fairly.

Testing a Single Mean Module 16. Tests of Significance Confidence intervals are used to estimate a population parameter. Tests of Significance or Hypothesis.

Review from before Christmas Break. Sampling Distributions Properties of a sampling distribution of means:

 Confidence Intervals  Around a proportion  Significance Tests  Not Every Difference Counts  Difference in Proportions  Difference in Means.

Confidence Interval You sample 36 apples from your farm’s harvest of over 200,000 apples. The mean weight of the sample is 112 grams (with 40 gram sample.

Interpreting Estimates Intervals for Proportions Intervals for Known Sigma Intervals for Unknown Sigma Sample Size

Problem 1 Suppose 40% of registered voters in a certain town are Democrats. You take a simple random sample of 80 voters. If your survey avoids biases,

Topics: Essentials Hypotheses Testing Examples

One sample Tests & Intervals on the Calculator

Chapter 23 Part 3 Examples.

One-Sample Inference for Proportions

Section 9-1 Review and Preview.

Comparing Two Proportions

Comparing Two Populations or Treatments

Math 4030 – 10a Tests for Population Mean(s)

Chapters 20, 21 Hypothesis Testing-- Determining if a Result is Different from Expected.

CHAPTER 10 Estimating with Confidence

Inferences Based on a Single Sample

Comparing Two Proportions

MATH 2311 Week 14 (Test 3 Review).

Inferences About Means from Two Groups

Hypothesis Tests for a Population Mean,

Central Limit Theorem General version.

A 95% confidence interval for the mean, μ, of a population is (13, 20)

Confidence Intervals for Proportions

Hypothesis Testing Two Proportions

MATH 2311 Section 4.4.

Introduction to Econometrics

Lesson Use and Abuse of Tests.

Business Statistics, 5th ed. by Ken Black

Do Now Take out review so I can come check

What are their purposes? What kinds?

Hypothesis Testing and Confidence Intervals

Chapter Outline Inferences About the Difference Between Two Population Means: s 1 and s 2 Known.

Warm Up Consumers of diet food products are concerned about the number of calories in each meal. A manufacturer advertises the number of calories in a.

Chapter 8: Confidence Intervals

Inference about Two Population Proportions

Warm Up A Gallup poll asked 1600 adults in the U.S. “Did you attend church in the past 7 days?” 715 people said yes. Assume the survey used a simple.

Chapter 9 Lecture 3 Section: 9.3.

MATH 2311 Section 4.4.

Testing a Claim About a Mean:  Known

Presentation transcript:

Mixed Examples of Hypothesis Testing & Confidence Intervals

Example 1 An insurance company is reviewing its current policy rates. When originally setting the rates they believed that the average claim amount was $1,800. They are concerned that the true mean is actually higher than this, because they could potentially lose a lot of money. They randomly select 40 claims, and calculate a sample mean of $1,950. Assuming that the standard deviation of claims is $500, and set α = .05, test to see if the insurance company should be concerned.

Example 2 A Gallup poll asked Americans to rate their life on a scale of 0 to 10 (0 being the worst possible life and 10 being the best). The 1,000 people who have a television set reported a mean of 6.07 with a standard deviation of 1.1. Of the 300 people without a television set, the mean score was 4.47 with a standard deviation of 2.8. http://www.gallup.com/poll/105850/Ownership-May-Good-WellBeing.aspx Form a 90% confidence interval for the mean difference.

Example 3 Suppose the Acme Drug Company develops a new drug, designed to prevent colds. The company states that the drug is equally effective for men and women. To test this claim, they chose a simple random sample of 100 women and 200 men from a population of 100,000 volunteers. At the end of the study, 38% of the women caught a cold; and 51% of the men caught a cold. Based on these findings, can we reject the company's claim that the drug is equally effective for men and women? Use a 0.05 level of significance.

Example 4 A hospital wants to get an estimate for infection rates of patients coming out of surgery. They observe a random sample of 120 patients who come out of surgery and find that 15 of them develop an infection while recovering. Construct a 95% confidence interval for the infection rate at this hospital. Explain what this confidence interval means. If the hospital wanted to narrow its confidence interval, what should it do?

Example 5 A sample of 40 sales receipts from a grocery store has a mean of $137 and a standard deviation of $30.2. Use these values to test whether or not the mean sales at the grocery store is less than $150.