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Hypothesis Testing

Test hypotheses and sample size requirement

1. A study was conducted to estimate the mean amount spent on birthday gifts for a typical family having two children. A sample of 150 was taken, and the mean amount spent was $225. Assuming a standard deviation equal to $50, find the 95% confidence interval form, the mean for all such families. 2. In testing the hypothesis,

Null and alternative hypotheses

If John Smith is charged with a crime under the U.S. legal system and is brought to trial, what are the null and alternative hypotheses that the judge, the jury, and the prosecution must work under? If the jury decides in favor of John Smith does this mean that he has been proven innocent? What about if the jury finds against hi

Hypothesis Testing: One-tailed and Two-tailed Testing

I've been trying to understand the differences between one tailed and two tailed testing, t and z testing and p value. I think I understood #5 but need some help with #18, 23 and 44. 18. The management of White Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the

Calculating Upper and Lower Control Limits

A particular magazine typically has 65% subscription renewals. A new advertising campaign is introduced to see if this can be increased. To monitor renewals, a sample of 300 subscribers is taken each month to see what percentage renew their subscription. What are the upper and lower control limits for a control chart for the

Consequences of Type I and Type II Errors

You are a water quality tester, working for the EPA. You are testing the water in a stream just below the point where a major manufacturing company runs water from its plant into the stream. In particular, you are testing for the presence of a pollutant that is supposed to be held at a mean level of 10 ppm. You test the follo

Z-Statistic, T-Statistic and P-value

1. We have now studied two statistics Z and t. Compare and contrast the use of these two statistical tests, with particular attention to the quantity and quality of the data we use in each test. Is one test better than the other? 2. In research the concept of p value is useful to interpret the results of a hypothesis test.

Statistics - highway mileage obtained from 20 automobiles

The data to the left are the highway mileage obtained from 20 automobiles of the same make and model driven under normal conditions by 20 different owners. a. The sticker on the automobile claims that cars of this type get an average of 30 miles per gallon. However the average of these 20 autos is only 28.6 miles per gallon.

A statistics question

Dear: I need help with the following sample question. Many thanks! Could you offer me related data and detailed explanations to the sub-questions so that I can attack similar problems? Thanks! The question: We will run a regression to test whether the Random Walk Model describes daily adjusted closing prices for S

Statistics Questions

Please see attached file for full problem description. Chapter 10 For Exercises 1 & 3 answer the questions: (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 H0? (e) What is the p-value? Interpret it. 1. The following in

ANOVA problems

Please see attached file for full problem description. 1- At LLD Records, some of the market research of college students is done during promotions on college campuses, while other market research of college students is done through anonymous mail, phone, internet, and record store questionnaires. In all cases, for each new C

Hypothesis Testing - Dozenol

The nighttime cold medicine Dozenol bears the label indicating the presence of 600 mg of acetaminophen in each fluid ounce of drug. The Food and Drug administration randomly selected 98 one ounce samples and found that the mean acetaminophen is 575 mg, whereas the standard deviation is 55 mg. Use a 21% significance level and tes

Statistics Review - Multiple Choice - Analysis of variance

1. Variance is... A. The average of the squared deviation from the mean. B. A measure of variability of data values about the mean. C. A measure of dispersion. D. All of the above. F. None of the above. 2. Analysis of variance means... A. We compute the variances of the variables observed in the study.

Testing of hypothesis for proportion

1-Testing for categories with different proportions. Here are the observed frequencies from four categories; 5,10,10,20. Assume that we want to use a 0.05 significance level to test the claim that the four categories have proportions of 0.20, 0.25, 0.25and 0.30, repectively a. What is the null hypothesis? b. What are the expec

Computer-interactive Data Analysis

1-Refer to the table below (Computer-interactive Data analysis) that lists the number of years that U.S president and popes and British monarch (since 1690) lived after their inauguration, election, or coronation. Determine whether the survival times for the three groups differ. See attachment for data. 2q-Archaeology: Skull

Compare two discounted plans

Using the attached data sheet to determine whether the discounted plan is superior to the non-discounted plan. Each pair of customers was chosen from the same block in the district. The data represents the number of days before the customer pays the bill. Provide a 95% confidence interval for the difference between the sample m

Determining Differences in Defect Levels

The Allbest software company owns two computer-manufacturing plants. Each plant produces the Ultimate computer model. Plant measurement has determined that 28 out of 452 tested computers at Plant A were defective and that 21 out of 505 tested at plant B were defective. Is there cause for concern that the defect levels at these t

Determine whether there is differences among the four tire brands

A Tire Company must determine which of four tire brands supplies the most amount of tire wear. It has been decided that all four tires are to be placed on each of eight cars. This design should allow us to compare tires without having differences in cars affect the comparison. Determine whether there is differences among the

Compare batteries

A research scientist obtained data on two battery brands. The response was how many hours of life were obtained for each battery. Analyze the following data using the six step approach to determine whether there is enough evidence to show that the AAA battery last longer than the BBB battery: AAA BBB 73 74 68 64 78 63

Testing Procedures and Five-Step Hypothesis Testing

Need Help with the following exercises: I have attached the five-step hypothesis testing procedure 14. The null and alternate hypotheses are: H0: 1  2 H1: 1  2 A random sample of 15 observations from the first population revealed a sample mean of 350 and a sample standard deviation of 12. A random sample of 17 obse

T-tests , significance and variance

Refer to the real estate data which report information on the homes sold in Denver Colorado year at: .A. At the .05 significance level can we conclude that there is a difference in the mean selling price of the homes with a pool and hoes without a

Hypothesis testing problems - The Rocky Mountain

The Rocky Mountain district sales manager of Rath Publishing, Inc., a college textbook publishing company, claims that the sales representatives make an average of 40 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 28 sales representatives reveals that the

Hypothesis test of a proportion

Please review the attached problem and help. A department store manager claims that at least 45% of persons who visited this store make a purchase. In a sample of 400 persons who visited the store 150 made a purchase. Test the manager's claim at the 3% significance level. a. State the null and alternate hypothesis. b. D


Can you assist me in putting together a z test using the information below ... or if we use a different example? Due to increase in product demand, management needs to increase labor production hours by an estimated 270 hours. Any-Business currently has 30 production employees whose hourly wages varies from $7.50 - $8.50 per

Risk of Drinking Water

In 1854, John Snow, a medical doctor hypothesized that there was a relationship between drinking water supply and cholera in London. The two major companies that supplied water to homes in London both got their water from the Thames River which runs through the city. The Lambeth Company pumped from upstream of London. The Southw