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Hypothesis Testing

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

P-value

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

Calculating the Rejection Region

A State University uses thousands of fluorescent light bulbs each year. The brand of bulb it currently uses has a mean life of 900 hours. A manufacturer claims that its new brands of bulbs, which cost the same as the brand the university currently uses, has a mean life of more than 900 hours. The university has decided to purcha

Compare the Concepts of Estimation and Hypothesis

11. From the population of unknown mean μ and a standard deviation σ = 5.0, a sample of n= 100 is selected and the sample mean 40.6 is found. Compare the concepts of estimation and hypothesis testing by answering the following: a. Determine the 95% confidence interval for μ. b. Complete the hypothesis test

Business Stats

(See attached file for full problem description) --- 15 pts. 4. We want to develop a model to predict the selling price of a home based upon the assessed value. A sample of 30 recently sold single-family houses is selected. The results are as follows: Observation Assessed Value (000) Selling Price(000) 1 78.17 94.10 2 8

Testing Categorical Probabilities: One-Way Tables

Inc. Technology reported the results of an Equifax/Harris Consumer Privacy Survey in which 328 Internet users indicated their level of agreement with the following statement:"The government needs to be able to scan internet messages and user communications to prevent fraud and other crimes." The number of users in each response

Inferences based on 2 samples

Excess postexercise oxygen consumption (EPOC) describes the energy expended during the body's recovery period immediately following aerobic exercise. A journal published a study designed to investigate the effect of fitness level on the magnitude and duration of EPOC. Ten healthy young adult males volunteered for the study. Five

Inferences based on Single Samples

A consumer protection group is concerned that a ketchup manufacturer is filling its 20-ounce family-size containers with less than 20 ounces of ketchup. The group purchases 10 family-size bottles of this ketchup, weighs the contents of each, and finds that the mean weight is equal to 19.86 ounces, and the standard deviation is e

Inferences Based on Single Sample

An article in the Annals of the Association of American Geographers (June 1992) revealed that only 133 of 337 randomly selected residences in Los Angeles County were protected by earthquake insurance. -What are the appropriate null and alternative hypotheses to test the research hypothesis that less than 40% of the residents

Sampling and X-bar Distribution

A Company produces candy on a production line. When operating properly, the production process will produce an average of u=140 pounds of candy per hour with a standard deviation of o=20 pounds of candy per hour. It is also known that the distribution is skewed left. In order to monitor the assembly process, 100 hours are ran

Null hypothesis

Here are some things I need help with: ? ALWAYS write out the NULL & HYPO (they come as a set) even if the assignment does not ask you to do so ? Even though you write hypotheses using mathematical notations, it is important to also get in the habit of writing them in words too... things do get more complicated ? Alwa

Car Dealership, Level of Significance, Digital Camera

4. Car dealership chain owner wants to increase the car sales of his chain. He wants to determine which factors influence the sales performance. Owner thinks that the following factors have a significant impact on sales performance: X1 = number of years of experience as a car sales person X2 = age Sales performance is me

Statistical Hypothesis Testing: Crusty The Clown' Cereal

1. The sales of Crusty The Clown cereal since 2000 are: Year Code Sales ($ millions) 2000 1 5 2001 2 7 2002 3 6 2003 4 10 2004 5 12 What is the sales forecast for 2005? 2. The owner of a car dealership wants to determine whether there is a relation between the income level and the ty

Hypothesis testing

I am a manufacturer of refrigerators. Historically ( the last year of manufacturing) I averaged 200 units a week with a 10 unit standard deviation. Recently we upgraded some of the line to improve production. I took a random sample over 30 random weeks and came up with a sample average of 205 units Did I make improvements

Test of hypothesis

3-10. A researcher interested in the senses of taste and smell has carried out extensive studies in which university students are given each of 20 different foods (apricot, chocolate, cherry coffee, garlic, and so on). She administers each food by dropping a liquid on the tongue. Over the entire student population at her univers

Dependent Variables and Independent Variables

The owner of Maumee Ford-Mercury wants to study the relationship between the age of a car and its selling price. Listed below is a random sample of 12 used cars sold at the dealership during the last year. Car Age (years) Selling Price ($0.00) 1 9 8.1

Hypothesis Test on population proprotion

Tourism is one consideration for CoffeeTime's future, A survey of 1,233 visitors to mumbai last year revealed that 110 visited a small cafe during their visit. Laura claims that 10% of tourists will include a visit to a cafe.

Statistics Review - Significance Level, P-Value

1. A financial analyst wants to compare the turnover rates, in 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 m

Statistics Review Problem Set

1. The following is a hypothetical set of anxiety scale scores from a population of students being seen at a college counseling center: 5 16 47 6 18 50 9 25 50 10 46 50 12 47 78 What are the Z and the T scores of the person who scored 6? 18? Of the two people who scored 47? Of the person who scored 78? Why is it not a

Statistic Mean and Sampling

Clark Heter is an industrial engineer at Lyons Products. He would like to determine whether there are more units produced on the afternoon shift than on the day shift. A sample of 54 day-shift workers showed that the mean number of units produced was 345, with a standard deviation of 21. A sample of 60 afternoon-shift workers sh

Hypothesis Testing - Highschool Smoking

2) In 1999 the Center of Disease Control estimated that about 34.8% of high-school students smoked cigarettes. They established a national health goal of reducing that figure to 16% by the year 2010. To that end, they hoped to achieve a reduction to 30% by the end of 2001. Early in 2002 they released a research study in which on

Statistics Data Help

I am doing a project where I am comparing the accuracy and reproducibility of 3 different force gauges with varied angles and applied pressures. All of the gauges have a 50 lb. capacity. They will all be tested with 0-30 lbs in 5 lb increments of applied load/pressure. They will also be tested at 0 degrees (true perpendicular)