Use the following information to answer the next three exercises. Neuroinvasive West Nile virus is a severe disease that affects a person's nervous system . It is spread by the Culex species of mosquito. In the United States in 2010 there were 629 reported cases of neuroinvasive West Nile virus out of a total of 1,021 reported cases and there were 486 neuroinvasive reported cases out of a total of 712 cases reported in 2011. Is the 2011 proportion of neuroinvasive West Nile virus cases more than the 2010 proportion of neuroinvasive West Nile virus cases? Using a1%level of significance, conduct an appropriate hypothesis test.
  • "2011" subscript: 2011 group.
  • "2010" subscript: 2010 group

(a) a test of two proportions
(b) a test of two independent means
(c) a test of a single mean
(d) a test of matched pairs.

Short Answer

Expert verified

Answer is (a)

Step by step solution

01

Given information

Conduct an appropriate hypothesis test with a 1% level of significance.

02

Explanation

A z-test for two proportions compares two proportions to see if they are the same. The proportions are equal is the null hypothesis (H0)for the test. H1is the alternative hypothesis, which states that the proportions are not equal.

according to the information given in the question, we know that there are two samples:

2011 group and 2010 group. it is a proportionate test.

Therefore option (a) is the correct answer

03

Incorrect answer 

The two-sample t-test (also termed as the independent samples t-test) is just a statistical approach for determining if two variable' estimated population means are equal. Here, we know the samples.

When you compare the mean value to another predicted value, you're testing a single mean.

Therefore option b, c, and d are incorrect.

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Most popular questions from this chapter

Two types of phone operating system are being tested to determine

if there is a difference in the proportions of system failures (crashes). Fifteen out of a random sample of 150 phones with OS1had system failures within the first eight hours of operation. Nine out of another random sample of 150 phones with OS2had system failures within the first eight hours of operation. OS2is believed to be more stable (have fewer crashes) than OS1.

What can you conclude about the two operating systems?

Use the following information to answer the next five exercises. Two metal alloys are being considered as material for ball bearings. The mean melting point of the two alloys is to be compared. 15 pieces of each metal are being tested. Both populations have normal distributions. The following table is the result. It is believed that Alloy Zeta has a different melting point.

State the null and alternative hypotheses.

Use the following information to answer the next 12 exercises: The U.S. Center for Disease Control reports that the mean life expectancy was 47.6 years for whites born in 1900 and 33.0 years for nonwhites. Suppose that you randomly survey death records for people born in 1900 in a certain county. Of the 124 whites, the mean life span was 45.3 years with a standard deviation of 12.7 years. Of the 82 nonwhites, the mean life span was 34.1 years with a standard deviation of 15.6 years. Conduct a hypothesis test to see if the mean life spans in the county were the same for whites and nonwhites.

Sketch a graph of the situation. Label the horizontal axis. Mark the hypothesized difference and the sample difference. Shade the area corresponding to the p-value.

What is the sample mean difference?

In symbols, what is the random variable of interest for this test?

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