Explain the confidence interval, Managerial Economics

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

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
Related Questions
Internal and External factors of business operation External factors : A firm can't exercise any control over these factors. Thepolicies, plans and programmes of the firm m

What is the difference between monopoly and perfect competition? Monopoly versus Perfect Competition: 1. Perfect competition is equal to monopoly competition, at the perfe

A firm's technology needsit to combine 5 person-hours of labor with 3 machine-hours to make 1 unit of output. The firm has 15 machines in place and the wage rate rises from $10 per

Describe the Optimisation of managerial economics Optimisation techniques are perhaps the most vital to managerial decision making. Given that alternative courses of action are

Q. Types of production function? Production function is of two different forms:  The variable proportion production function The fixed proportion production functio

The only road connecting two populated islands is currently a freeway. During rush hour, there is congestion because of the heavy traffic. The marginal external cost from congestio

Factors affecting the total market demand These are broadly divided into the determinants of demand and conditions of demand. (a)      Own price of the product This

Collective bargaining Collective bargaining  refers to the whole process by which trade unions and employers (or their representatives) arrive at an enforce agreements.  Tra

Describe the Forecasting method in managerial economics It is a technique or a method to predict many future aspects of a business or any other operation. For illustration, a r

Q. Show the uses of income elasticity? A few significant uses of income elasticity are as follows: First, concept of income elasticity can be used to approximately compute t