I would like to test a hypothesis that the percentage of people who consider themselves as conservatives today is lower than it was 20 years ago. Conveniently enough, my old professor has data from 20 years ago when he conducted a similar survey. The number of people 20 years ago who identified as conservative in his survey was 314 out of 612 total. I conduct a survey today and find that out of the 415 people i surveyed, 198 considered themselves to be conservative. If i wish to present my findings with a level of significance of .05, what conclusion would i draw?

options:

based on the data, there's evidence of a decrease in those who identify as conservative.

based on the data, there's no evidence of a decrease in those who identify as conservative.

based on the data, there's evidence of an increase in those who identify as conservative.

based on the data, there's no evidence of an increase in those who identify as conservative.

The Centers for Disease Control reported the percentage of people 18 years of age and older who smoke (CDC website, December 14, 2014). Suppose that a study designed to collect new data on smokers and nonsmokers uses a preliminary estimate of the proportion who smoke of .30.

a. How large a sample should be taken to estimate the proportion of smokers in the population with a margin of error of .02 (to the nearest whole number)? Use 95% confidence.

b. Assume that the study uses your sample size recommendation in part (a) and finds 520 smokers. What is the point estimate of the proportion of smokers in the population (to 4 decimals)?

c. What is the 95% confidence interval for the proportion of smokers in the population (to 4 decimals)?

( ,  

19. Researchers believe that a higher percentage of males are afflicted with cysturina than females. Suppose of the 50 individuals, 15 were females and the remainder were males. Using 99% confidence, estimate the proportion of females with cysturina. Then estimate the proportion of females afflicted with cysturina at 96% confidence.

How much PE does glucose have compared to gasoline (express as a percentage)?

$1M is available to invest in S or B. The percentage yield on each investment depends on whether the econ has a good or bad year.

Econ has a Good year    Econ has a Bad year

Yield on S    22% of 1M 10% of 1M

   (i.e. $220,000)    ($100,000)

Yield on B 16% of 1M 14% of 1M

($160,000) ($140,000)

It is equally likely (50%) that the econ will have a good or bad year.

For $10,000, a firm can be hired to forecast the state of the econ. The firm's forecasts have the following probabilities:

p(Good forecast | Econ is good) = .8

p(GF | EIB) = .2

It is equally likely (50%) for EIG & EIB to occur

a) Calculate the following:

p(EIG | GF) =

p(EIB | GF) =

p(EIG | BF) =

p( EIB | BF) =

b) Draw a decision tree to determine to invest in S or B to maximize expected profits. Should the firm be hired?

c) What are the values of the EVSI and EVPI?

The home run percentage is the number of home runs per 100 times at bat. A random sample of 43 professional baseball players gave the following data for home run percentages.

(a) Use a calculator with mean and standard deviation keys to find x and s. (Round your answers to two decimal places.)

(b) Compute a 90% confidence interval for the population mean μ of home run percentages for all professional baseball players. Hint: If you use the Student's t distribution table, be sure to use the closest d.f. that is smaller. (Round your answers to two decimal places.)

(c) Compute a 99% confidence interval for the population mean μ of home run percentages for all professional baseball players. (Round your answers to two decimal places.)

$1M is available to invest in S or B. The percentage yield on each investment depends on whether the econ has a good or bad year.

Econ has a Good year    Econ has a Bad year

Yield on S    22% of 1M 10% of 1M

   (i.e. $220,000)    ($100,000)

Yield on B 16% of 1M 14% of 1M

($160,000) ($140,000)

It is equally likely (50%) that the econ will have a good or bad year.

For $10,000, a firm can be hired to forecast the state of the econ. The firm's forecasts have the following probabilities:

p(Good forecast | Econ is good) = .8

p(GF | EIB) = .2

It is equally likely (50%) for EIG & EIB to occur

a) Calculate the following:

p(EIG | GF) =

p(EIB | GF) =

p(EIG | BF) =

p( EIB | BF) =

b) Draw a decision tree to determine to invest in S or B to maximize expected profits. Should the firm be hired?

c) What are the values of the EVSI and EVPI?

An online bookstore predicts that the percentage of college students buying anthropology books online is not equal to 45 %, on average. Several of the bookstore’s client universities would like to know if this is likely, so the online bookstore decides to do a hypothesis test at a 10% significance level. Data is collected from 11 universities providing the following information: H0: μ=45; Ha: μ≠45 x¯=51 σ=4 α=0.1 (significance level) The test statistic is z0=x¯−μ0σn√=51−45411√=4.97 The critical values are −z0.05=−1.64 and z0.05=1.64. Conclude whether to reject or not reject H0, and interpret the results. Based on this context and the null and alternative hypothesis, what type of hypothesis test should be used? Use the curve below to show your answer. Select the appropriate test by dragging the blue point to a right-, left- or two-tailed diagram. The shaded area represents the rejection region. Then, set the critical value(s) on the x-axis by moving the purple slider on the right. Provide your answer below:

How does the percentage of voters who are renters (as opposed to owners) affect the incentives for politicians to propose rent controls? Does this incentive depend on the likelihood that renters are less likely to vote in local elections than are owners of apartments and houses? Why do you suppose renters are less likely to vote in local elections? Explain.

Use the percentage method to compute the federal income taxes to withhold from the wages or salaries of each employee. If an amount is zero, enter "0". If required, round your calculations and final answers to the nearest cent.

Click here to access the Table of Allowance Values.

Click here to access the Percentage Method Tables.