HOMEWORK P.410:

33) 0.0060; reject the null hypothesis.34) 0.7264; fail to reject the null hypothesis35) 0.0107; reject the null hypothesis36) 0.0016; reject the null hypothesis

38) There is suffi cient evidence to support the claim that the percentage of on-time U.S. airlines fl ights is less than 75%.

39) There is not suffi cient evidence to warrant rejection of the claim that the percentage of Americans who know their credit score is equal to 20%.

Testing a Claim About a Proportion

SECTION 8.3

Medicine: Are certain medications effective? Can pregnant women correctly guess the sex of their

babies? Do different medical procedures provide the results they

promise?Entertainment:

How effective are different commercials? How many people watch the Super Bowl – are these high

priced ad spaces worthwhile? Business

Do products work as advertised? How many people might be interested in a new product?

Create your own!

WHY TEST A CLAIM?

Section 8.2

We looked at the individual components of a hypothesis test and how they each work.

Section 8.3

We will test different proportion claims to determine if they are true or not.

WHAT’S THE DIFFERENCE?

Step 0: Check Requirements. Simple Random Sample Conditions for a Binomial Distribution are satisfied and

Step 1: Determine and . Step 2: Select an appropriate (normally .05

or .01)Step 3: Calculate the appropriate test statisticStep 4: Determine the P-value (Draw a picture)Step 5: Reject if the P-value , fail to reject if notStep 6: State conclusion in simple non-technical

terms

THE HOW TO

The XSORT is a method of gender selection that promises couples an increased chance of having a baby girl. Among 726 babies born to

couples using the XSORT method in an attempt to have a baby girl, 668 of the babies

were girls and the others were boys. Use these results with a 0.05 significance level to

test the claim that among babies born to couples using the XSORT method, the

proportion of girls is greater than the value of 0.5 expected with no treatment.

THE PROBLEM

Step 0: Check Requirements. Simple Random Sample Conditions for a Binomial Distribution are satisfied and

THE HOW TO

Step 1: Determine and .

THE HOW TO

Step 2: Select an appropriate (normally .05 or .01)

THE HOW TO

Step 3: Calculate the appropriate test statistic

THE HOW TO

Step 4: Determine the P-value (Draw a picture)

THE HOW TO

Step 5: Reject if the P-value , fail to reject if not

THE HOW TO

Step 6: State conclusion in simple non-technical terms

THE HOW TO

A study addressed the issue of whether pregnant women can correctly guess the sex of their baby. Among the 104 subjects, 55% correctly guessed the sex of the baby. How

many of the 104 made correct guesses?

FINDING THE NUMBER OF SUCCESSES X

If you can create a confidence interval using the sample statistic, and it does

not contain the value for the parameter given by the null hypothesis, you can

reject the null hypothesis.

SIDE NOTE: CONFIDENCE INTERVAL METHOD

p. 421 #9-12

HOMEWORK