a. Determine the sample proportion.

b. Decide whether using the one-proportion z-test is appropriate.

c. If appropriate, use the one-proportion z-test to perform the specified hypothesis test.

x=35

n=50

H0:p=0.6

role="math" localid="1651304589496" Ha:p>0.6

α=0.05

Short Answer

Expert verified

(a) The sample proportion is 0.7.

(b) It is appropriate to use one proportion z-test.

(c) The hypothesis H0is not rejected.

Step by step solution

01

Part (a) Step 1: Given information

The given data is

x=35

n=50

H0:p=0.6

Ha:p>0.6

α=0.05

02

Part (a) Step 2: Explanation

The expression for the sample proportion is

p^=xn

The sample proportion is calculated as

p^=3550

=0.7.

03

Part (b) Step 1: Given information

The given data is

x=35

n=50

H0:p=0.6

Ha:p>0.6

α=0.05

04

Part (b) Step 2: Explanation

Let's test the hypothesis

H0:p=0.6

H0:p>0.6

Calculate the value ofnp0

np0=(50)(0.6)

=30

Calculate the value of

n1-p0=(50)(1-0.6)

=50(0.4)

=20

Both np0and n(1-p0)have value greater than 5. So, one proportion z-test is appropriate to use.

Therefore, it is appropriate to use one proportion z-test.

05

Part (c) Step 1: Given information

The given data is

x=35

n=50

H0:p=0.6

Ha:p>0.6

α=0.05

06

Part (c) Step 2: Explanation

Write the expression for z

z=p^-p0P01-P0n

Then the value is calculated as

z=0.7-0.60.6(1-0.6)50

=0.10.0693

=1.4434

And also, α=0.05

From the standard table

z0.05=1.645

A positive value is taken because the test is Right-handed.

The test statistic falls in the acceptance region.

So, the hypothesis H0is not rejected.

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Most popular questions from this chapter

In this Exercise, we have given the number of successes and the sample size for a simple random sample from a population. In each case,

a. use the one-proportion plus-four z-interval procedure to find the required confidence interval.

b. compare your result with the corresponding confidence interval found in Exercise 11.25-11.30, if finding such a confidence interval was appropriate.

role="math" localid="1651327118166" x=35,n=50,99%level

In discussing the sample size required for obtaining a confidence interval with a prescribed confidence level and margin of error, we made the following statement: "... we should be aware that, if the observed value of p^is closer to 0.5than is our educated guess, the margin of error will be larger than desired." Explain why.

One-Proportion Plus-Four z-Interval Procedure. To obtain a plus four z-interval for a population proportion, we first add two successes and two failures to our data (hence, the term "plus four") and then apply Procedure 11.1on page 454to the new data. In other words, in place of p^(which is x/n), we use p~=(x+2)/(n+4). Consequently, for a confidence level of 1-α, the endpoints of the plus-four z-interval are

p~±za/2·p~(1-p~)/(n+4)

As a rule of thumb, the one-proportion plus-four z-interval procedure should be used only with confidence levels of 90% or greater and sample sizes of 10 or more.

Fill in the blanks.

a. The mean of all possible sample proportions is equal to the

b. For large samples, the possible sample proportions have approximately a distribution.

c. A rule of thumb for using a normal distribution to approximate the distribution of all possible sample proportions is that both and are or greater.

we have given a likely range for the observed value of a sample proportion P^

0.2to0.4

a. Based on the given range, identify the educated guess that should be used for the observed value of p^to calculate the required sample size for a prescribed confidence level and margin of error.

b. Identify the observed values of the sample proportion that will yield a larger margin of error than the one specified if the educated guess is used for the sample-size computation.

The Organization for Economic Cooperation and Development (OECD) conducts studies on unemployment rates by country and publishes its findings in the document Main Economic Indicators. Independent random samples of 100and75 people in the civilian labor forces of Finland and Denmark, respectively, revealed 7and 3 unemployed, respectively. Find a 95% confidence interval for the difference between the unemployment rates in Finland and Denmark.

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