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Hypothesis Testing

Rejection Rate Hypothesis

It is suspected that the rejection rate for a plastic-cup-molding machine is dependent on the temperature at which the cups are molded. A series of short tests is conducted to examine this hypothesis with the following results: Temperature Total Production Number Rejected T1 150

The Gibbs Baby Food Company wishes to compare the weight gain of infants...

The Gibbs Baby Food Company wishes to compare the weight gain of infants using their brand versus their competitor's. A sample of 40 babies using the Gibbs products revealed a mean weight gain of 7.6 pounds in the first three months after birth. The standard deviation of the sample was 2.3 pounds. A sample of 55 babies using

Statistics Study Questions

(See attached file for full problem description) --- A. Circle the correct answer. 1. The null hypothesis is a claim about a. the size of the sample. b. the size of the population. c. the value of a sample statistics. d. the value of the population parameter. 2. when the null hypothesis is rejected, we conclude that

Hyopthesis testing

A financial analyst wants to compare the turnover rates, I percent, for shares of oil-related stocks versus other stocks, such as GE and IBM. She selected 32 oil related stocks and 49 other stocks. The mean turnover rate of oil-related stocks is 31.4 percent and the standard deviation 5.1 percent. For the other stocks, the mean

Hypothesis testing and Regression

1. Bi-lo Appliance Stores has outlets in several large metropolitan areas. The general sales manager plans to air a commercial for a digital camera on selected local TV stations prior to a sale starting on Saturday and ending Sunday. She plans to get the information for Saturday - Sunday digital camera sales at the various outle

Hypothesis test

Your director has banned the use of all artificial fingernails, claiming their use contributes to patient infections in the unit. After multiple discussions the director has allowed you to do a research study to determine if the use of artificial fingernails causes increases in infection rates. You would really like to prove tha

Hypothesis test

Test the hypothesis that a population mean is 14 against the alternate that it is NOT 14. Use an alpha of 1%. A sample of 500 will be taken. The sample standard deviation is 6.4. The computed sample mean is 14.7356. ? Use the full, formal, hypothesis testing model. ? Calculate the p-value. ? State your conclusions both in

Hypothesis test - expanding economy

Each month the National Association of Purchasing Managers publishes the NAPM index. One of the questions asked on the survey to purchasing agents is: Do you think the economy is expanding? Last month, of the 300 responses 160 answered yes to the question. This month, 170 of the 290 responses indicated they felt the economy was

Hyopthesis testing

A board of directors at the Anchor Pointe Marina is studying the usage of boats among its members. A sample of 30 members who have bots 10 to 20 feet in length showed that they used their boats an average of 11 days last July. The standard deviation of the sample was 3.88 days. For a sample of 40 members with 21 to 40 feet in le

Hypothesis test

An official of the Iowa department of Highways wants to compare the useful life, in months, of two brands of paint used for striping roads. The mean number of months Cooper Paint lasted was 36.2, with a standard deviation of 1.14 months. The official reviewed 35 road stripes. For king Paint, the mean number of months was 37.0, w

Hypothesis Testing and Tests for Independence for a construction company

A construction company wants to determine if the likelihood of having an injury is related to the type of worker. Over the past decade the company has had an average total workforce of 2560 workers. On average 601 of these were tradesmen, 381 were apprentices and the rest were labourers. During that decade there was a total of 4

Hypothesis testing question

Answer the following question: a). Is this a one- or two-tailed test? b). What is the decision rule? c). What is the value of the test statistic? d). What is your decision regarding Ho? e). What is the p-value? Interpret it. The following information is available. Ho:u< 10 H1:u> 10 The sample mean is 12 for a sa

Franklin Park Mall Hypothesis Testing

The owners of the Franklin Park Mall wished to study customer shopping habits. From earlier studies the owners are under the impression that a typical shopper spends 0.75 hours at the mall, with a standard deviation of 0.10 hours. Recently the mall owners added some specialty restaurants designed to keep shoppers in the mall l


Chapter review questions attached. --- 1. If it is important to reject a false null hypothesis, the B probability should be: a. small b. large c. close to 1.0 d. negative e. impossible to tell? 3.. The manufacturer of a refrigerator system for beer kegs produces refrigerators which are supposed to maintain a true mean

Random Selection of MP3 Players

The manufacturer of an MP3 player wanted to know whether a 10 percent reduction in price is enough to increase the sales of their product. To investigate, the owner randomly selected eight outlets and sold the MP3 player at the reduced price. At seven randomly selected outlets, the MP3 player was sold at the regular price. Re

Hypothesis Testing: Fry Brothers Heating and Air Condition, Inc.

Fry Brothers Heating and Air Conditioning, Inc. employs Larry Clark and George Murnen to make service calls to repair furnaces and air conditioning units in homes. Tom Fry, the owner, would like to know whether there is a difference in the mean number of service calls they make per day. A random sample of 40 days last year showe

Hyopthesis testing

An urban planner claims that, nationally, 20 percent of all families renting condominiums move during a given year. A random sample of 200 families renting condominiums in Dallas revealed that 56 had moved during the past year. At the .01 significance level, does this evidence suggest that a larger proportion of condominium owne

Hypothesis test

In the news recently a New Jersey representative wants to introduce a bill banning smoking while driving to save lives. What study would you design to support his case? What is the null hypothesis? Alternative hypothesis? How would you sample? How many would you include in your sample? What level of significance would you

Problems on Basic Statistical Concepts

I need some help on answer these questions with workings: (See attached file for full problem description) --- 1) What is the best point estimate of the a) population parameter? b) population variance? 2) A sample of 100 elements produced a mean of 48 and a standard deviation of 8. Find the 99% confidence interval for

Business Statistics 101

(1) If the number of miles per gallon achieved by all cars of a particular model has a mean of 25 and a standard deviation of 2, what is the probability that, for a random sample of 20 such cars, the average miles per gallon will be less than 24? Assume that the population distribution is normal. (a) .0125 (b) .1443 (c) .2

Comparisons Involving Proportions

One of the questions on a 2004 Business Week Survey was 'when making investment purchases, do you use full service or discount brokerage firms?'. Survey results, which is based on the indication of preference from 1000 respondents, showed that 28.4% of the respondents used only full services and discount brokerage firms. Use alp

Various First Year Statistic Problems

(See attached file for full problem description) --- For Exercise 1, assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. 1. N = 1200, x = 400, 99% confidence For exercise 2, use the sample data and confidence lev

How to Test a Hypothesis

I need help with hypothesis testing and excel. I have attached the sample database for use. Can you please explain how this is done in excel and what the statistical formulas are. I do know that for a hypothesis test with .05 or 95% must compute the z-value which is actual - predit/som var - how do I do this. 1. Test a h


A researcher is interested in determining the proportion of public elementary schools that have a mandatory school uniform policy. The researcher randomly sampled n=400 public elementary schools and found that 100 of the schools have a mandatory school uniform policy. Suppose the researcher found a test statistic of z=2.5 when

Inferences Based on Sample Size

A local tennis pro-shop strings tennis rackets at the tension (pounds per square inch) requested by the customer. Recently a customer made a claim that the pro-shop consistently strings rackets at lower tensions, on average, than requested. To support this claim, the customer asked the pro shop to string 10 new rackets at 55 psi