A concerned group of citizens wanted to know if the proportion of forcible rapes in Texas was different in 2011

than in 2010.Their research showed that of the 113,231violent crimes in Texas in 2011,7622of them were forcible rapes. In 2011,7439of the 104,873violent crimes were in the forcible rape category. Test at a 5%significance level.

Answer the following questions:

a. Is this a test of two means or two proportions?

b. Which distribution do you use to perform the test?

c. What is the random variable?

d. What are the null and alternative hypothesis? Write the null and alternative hypothesis in symbols.

e. Is this test right-, left-, or two-tailed?

f. What is the p-value?

g. Do you reject or not reject the null hypothesis?

h. At the ___ level of significance, from the sample data, there ______ (is/is not) sufficient evidence to conclude that

____________.

Short Answer

Expert verified

a. This is a test of two proportions.

b. The distribution to perform the test is the normal distribution.

c. The random variable is X.

d. H0:p1=p2Ha:p1p2

e. The test is two-tailed.

f. The p-value is 0.069.

g. We do not reject the null hypothesis.

h. At the 5% level of significance, from the sample data, there issufficient evidence to conclude that the proportion of forcible rapes in Texas in 2011and 2010are the same.

Step by step solution

01

Given information

The research showed that 113231violent crimes in Texas in 2010,7622of them were forcible rapes. In 2011,7439of the 104873violent crimes was in the forcible rape category. Test at 5%significant level.

02

Explanation (part a)

This is a test of two proportions.

03

Explanation (part b)

The distribution to perform the test is the normal distribution.

04

Explanation (part c)

The random variable Xis the number of forcible rapes in Texas every year.

05

Explanation (part d)

The null hypothesis H0: The proportion of forcible rapes in Texas in 2011and2010are same.

The alternative hypothesis: Ha: The proportion of forcible rapes in Texas in 2011and2010are different.

The null and alternative hypothesis:

H0:p1=p2Ha:p1p2

06

Explanation (part e)

The test is about the difference in the proportion of forcible rapes, therefore, it is two-tailed. Hence, the test is two-tailed.

07

Explanation (part f)

The p-value is0.0693

08

Explanation (part g)

Here, p-value>significantvalue,so we do not reject the null hypothesis.

09

Explanation (part h)

At the 5%level of significance, from the sample data, there issufficient evidence to conclude that the proportion of forcible rapes in Texas in 2011and2010are the same.

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