1.  According to an article in San Luis Obispo Tribune July 21, 2006 37% of the college freshman and 48% of the college seniors carry a credit balance from month to month. Suppose the reported percentages were based on random samples of 1000 college freshman and 1000 college seniors.

a)  Construct a 90% confidence interval for the proportion of college freshman carry a credit card balance from month to month.

b)  Construct a 90% confidence interval for the proportion of college seniors  carry a credit card balance from month to month.

c)  Explain why the 90% confidence intervals from a) and b) are not the same width.

2.  In AP-AOL sports poll (Associated press, December 18, 2005), 394 of 1000 randomly selected U.S. adults indicated that they considered themselves to be a baseball fans.   Of the 394 basketball fans, 272 stated that the thought the designated hitter rule should either be expanded to both baseball leagues or eliminated.

a)  Construct 95% confidence interval for the proportion of those who consider themselves to be baseball fans.

b)  Construct a 95% confidence interval for the proportion of those who consider themselves to be baseball fans that think the designated hitter rule should be expanded to both league or eliminated.

c)  Explain why the confidence interval of parts a0 and b) are not of same width though both have a confidence level of 95%

3. In a study of 1710 schoolchildren in Australia (Herald Sun, October 27, 1994), 1060 children indicated that they normally watch TV before school in the morning. (Interestingly, only 35% of the parents said their children watched TV beforeschool!) Construct a 95% confidence interval for true proportion of Australian children who say they watch TV before school.  What assumptions about the sample must be true before the method used to construct the interval valid.

4. In a survey conducted by Yahoo small business, 1432 of 1813 adults surveyed said they would alter their shopping habits if gas prices remain high.  The is SRS data and normally distributed. Based on these survey data is it reasonable to conclude that more than three quarters of adults plan to alter their shopping habits if the gas price remain high.

5. Associated press reported 38 percent of all felons who were released  from prison in 2003 landed back behind the bars by the end of the following year.  Explain why it is not be necessary to carry out a hypothesis test to determine if the proportion of felons released in 2003 was less than 40%.

6. In 2004 poll of 5500 cell phone users , 20% indicated that had received commercial messages and ads on their cell phone.  Is there sufficient evidence that the proportion of cell phone users who received commercial messages and ads was greater than the proportion of 0.13 reported for the previous year.

7. In a random sample of 117 female Hispanic drivers in Boston 68 were wearing seat belts.  Does the data give good reason to conclude that more than half of Hispanic female drivers in Boston wear seat belts.

Posted Date: 2/20/2013 4:18:05 AM | Location : United States

Ask an Expert

Related Discussions:- Explain the confidence interval, Assignment Help, Ask Question on Explain the confidence interval, Get Answer, Expert's Help, Explain the confidence interval Discussions

Write discussion on Explain the confidence interval
Your posts are moderated

Write your message here..

Related Questions

Limitations, limitations of managerial ecomomics limitations of managerial ecomomics

Structure of population and supply of labour, THE STRUCTURE OF POPULATION A... THE STRUCTURE OF POPULATION AND SUPPLY OF LABOUR The structure (also called age distribution or composition) of population, or the number of people in the different age groups

Identity economics, McDonalds has been operating in many Asian countries su... McDonalds has been operating in many Asian countries such as China, Singapore and Japan. However, McDonalds has yet to open its ?rst restaurant in Vietnam, a country with over 80 m

The multiplier, The Multiplier In his theory Keynes asserted that cons... The Multiplier In his theory Keynes asserted that consumption is a function of income, and so it follows that a change in investment, which we may call ΔI, meaning an incremen

Long-term policies to cure balance of payment deficits, Long-Term Policies ... Long-Term Policies One long term option of tackling balance of payments deficit is export promotion .  In the long run this is the best method of improving a balance of payme

Find out lowest efficiency wage and value , A risk-neutral agent's working ... A risk-neutral agent's working life has two periods. In each period, the agent can provide high effort (at personal cost $2,000) or low effort (at zero personal cost). In a given p

Factors influencing exchange rates, Factors influencing Exchange Rates ... Factors influencing Exchange Rates i.  Inflation:   Other things being equal, a country experiencing a high rate of inflation will experience a lower demand for its goods whil

Describe MRPL and profit maximisation, Q. Describe MRPL and profit maximisa... Q. Describe MRPL and profit maximisation? The common rule is that firm maximises profit by producing that quantity of output where marginal revenue equals marginal costs. Profi

Importance of income elasticity, Importance of Income Elasticity If a ... Importance of Income Elasticity If a country is experiencing economic growth, the income of the people will increase.  However, for those engaged in the production of goods wi

Short-run equilibrium, SHORT-RUN EQUILIBRIUM All firms are assumed to ... SHORT-RUN EQUILIBRIUM All firms are assumed to aim at maximizing profits or minimizing losses.  The monopolist controls his output or price, but not both. The monopoly maxi