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Hypothesis Testing

Statistics Problem Set: Rejecting the Null Hypothesis

3. Consider the hypothesis test given by H_0: u = 670 H_1: u does not equal 670 In a random sample of 70 subjects, the sample mean is found to be 678.2. The population standard deviation is known to be omega = 27. (a) Determine the P-value for this test. (Show work) (b) Is there sufficient evidence to

Statistics: White Blood Cell Counts

White blood cell counts are helpful for assessing liver disease, radiation, bone marrow failure, and infectious diseases. Listed below are recorded white blood cell counts. A. Use a 0.01 significance level to test the claim that females and males have different mean blood cell counts B. Construct a 99% confidence interval of t

Medecins Sans Frontières- Statistical Testing

My younger brother had a run in earlier with Medecins Sans Frontières. He narrowly escaped from an adverse verdict by the court. What he wants is that he be left alone to run his small cafe. He asked my oldest brother if he can conduct a survey for him about justice in the Canadian court. An initial survey was perform

Manufacturing Models

Outside Magazine tested 10 different models of day hikers and backpacking boots. The following data show the upper support and price for each model tested. Upper support was measured using a rating from 1 to 5, with a rating of 1 denoting average upper support and a rating of 5 denoting excellent upper support. Manufacturer

Hypothesis Thinking in the Court System

In the North American court system, a defendant is assumed innocent until proven guilty. In an ideal world, we would expect that the truly innocent will always go free, whereas the truly guilty ones will always be convicted. Now, let us tackle the following questions. In the context of the Type I error and Type II error, can

P-value Method: Comparing the BMI's of Miss America Winners

Please help with the following problem. Assume that a simple random sample has been selected from a normally distributed population and test the given claim. Use the p-value method for testing hypotheses. Identify the null and alternative hypotheses, test statistic, p-value, critical value, and state the final conclusion.

Examining raw data

Identify the null hypothesis, alternative hypothesis, test statistic, P-value and conclusion about the null hypothesis. Use the P-value method. California Speeding. Listed below are recorded speeds (in mi/h) of randomly selected cars traveling on a section of Highway 405 in Los Angles. That part of the highway has a posted s

Statistics: Evaluating significance using the p-value method

Identify the null hypothesis, alternative hypothesis, test statistic, p-value or critical value, and the conclusion about the null hypothesis. Use the P-value method. Question: When a fair die is rolled many times, the outcomes of 1, 2, 3, 4, 5, and 6 are equally likely, so the mean of the outcomes should be 3.5. The author d

Statistics: Using the p-value method

Question: Identify the null hypothesis, alternative hypothesis, test statistic, P-value or critical conclusion about the null hypothesis and final conclusion that addresses the original claim. Use the p-value method and use the normal distribution as an approximation to the binomial distribution. Gender selection for boys Th

Statistics Problem Set: Hypothesis Testing Using Samples

Problem 1: A study by Hewitt Associates showed that 79% of companies offer employees flexible scheduling. Suppose a researcher believes that in accounting firms this figure is lower. The researcher randomly selects 415 accounting firms and through interviews determines that 303 of these firms have flexible scheduling. With a 1%

Statistics Problem Set: Hypothesis Testing

1. What is the difference in average daily hotel room rates between Minneapolis and New Orleans? Suppose we want to estimate this difference by taking hotel rate samples from each city and using a 98% confidence level. The data for such a study follow. Use these data to produce a point estimate for the mean difference in the hot

Critiquing PERT

You decide to introduce the concept of PERT to a business who is struggling with project scheduling. One of the managers of the company tells you the following: "Well, we thought about PERT before actually. The best part about PERT is that it recognizes uncertainty in project time estimation as it is - there is no attempt to

30 Insulators Level of Significance: Evaluating Force

An organization thinks that if the electrical insulators break when in use, a short circuit might occur. To test the strength of the insulators, a hard core test will be performed to determine how much force is required to break the insulators. Force is measured by observing the number of pounds of force (lbs.) applied to the

Testing Research Hypotheses

Please help with the following problem. In playing the Lemonade Stand Game, Bob decreased his price per cup by two cents, from $.27 per cup to $.25 per cup. At the .05 level of significance, did net revenue increase? The data for weeks 3 and 4 are presented below; there were 30 observations in each week. Items to compar

Hypothesis Test: Fitness Camp Glasses

Researchers at the Cornell University Food and Brand Lab conducted an experiment at a fitness camp for adolescents (Wansink & van Ittersum, 2003). Campers were given either a 22-ounce glass that was tall and thin or a 22-ounce glass that was short and wide. Campers with the short glasses tended to pour more soda, milk, or juice

Choosing a Suitable Hypothesis Test

For each of the following three scenarios, state which hypothesis test you would use from among the four introduced so far: the z test, the single-sample t test, the paired-samples t test, and the independent-samples t test. (Note: In the actual studies described, the researchers did not always use one of these tests, often beca

Calculating customer satisfaction

Recall that "very satisfied" customers give the XYZ-Box video game system a rating that is at least 42. Suppose that the manufacturer of the XYZ-Box wishes to use a random sample of 65 satisfaction ratings to provide evidence supporting the claim that the mean composite satisfaction rating for the XYZ-Box exceeds 42. a) Lett

Creating Hypotheses

Assume you are the manager of a paint manufacturing factory. Your company has received complaints from customers that the containers hold less than the amount printed on them. On the other hand, corporate management is concerned that the containers hold more than the standard amount. You assign a statistician to verify these

T-Statistics Independent Samples

Numeric results for several independent-samples t tests are presented here. Decide whether each test is statistically significant, and report each result in the standard APA format. a. A total of 73 people were studied, 40 in one group and 33 in the other group. The test statistic was calculated as 2.126 for a two-tailed test

Uniform distribution of bicycle accidents

A bicycle safety organization claims that fatal bicycle accidents are uniformly distributed throughout the week. The table below shows the day of the week for which 778 randomly selected fatal bicycle accidents occurred. At ? = 0.10, can you reject the claim that the distribution is uniform? Complete parts (a) through (d) bel

Random Sampling Distribution Test

An automobile manufacturer advertises that the mean petrol consumption of its new hybrid car does not exceed 4.6 litres per 100 km. An independent company decides to test the manufacturer's claim by selecting a random sample of 16 vehicles and measuring the consumption of each. They have found that the petrol consumptions in lit

Errors and Their Implications

It has been said that from the point of view of the general population, Type I errors are particularly undesirable. This has been used as a justification for setting alpha at such low levels as .05 and .01. Does this make sense? Explain your response. What are the implications of making a Type I error, as compared to those o

Testing Assumptions.

For its validity, all hypothesis testing depends heavily on the assumption that the sample that is used was drawn using probability sampling techniques. Why is this important? What can you do if you just cannot use a probability sampling technique? (For example, suppose there is no good sampling frame available for the popul

One-tailed and Two-tailed Tests

You are doing a study examining the effects of studying method on academic achievement. All the students in your study take a course on genetics that lasts for 10 days. One group of students studies 20 minutes a day for 10 days. The second group studies once at the end of the course but for 200 minutes. What is a one-tailed t

Hypothesis Testing: One Sample Inference

Diabetes Plasma-Glucose levels are used to determine the presence of diabetes. Suppose the mean in (plasma-glucose) concentration (mg/dL) in 35 to 44-year-olds is 4.86 with standard deviation = 0.54. A study of 100 sedentary people in this group is planned to test whether they have a higher or lower level of plasma glucose t

Statistics - Critical Values

Write the claim mathematically and identify Hₒ and Hₐ. (b) Find the critical value(s) and identify the rejection region(s). (c) Find the standardized test statistic. (d) decide whether to reject or fail to reject the null hypothesis. A medical researcher says that at least 24% of adults are smokers. In a random sample o

Statistics Problem and Data Sets

e-grocers are companies that sells groceries over the internet. Customers open an online account, enter their orders, pay by credit card or debit card, and receive deliveries by truck. Several businesses think that it is means of convenience for busy customers who have no or very little time to go to a grocery store, buy groce

Hypothesis Testing Exercise

M&Ms® Project Part 5 Test the hypothesis (α = 0.05) that the population proportions of red and brown are equal (pred = pbrown). You are testing if their proportions are equal to one another, NOT if they are equal to one another AND equal to 13%. NOTE: These are NOT independent samples, but we will use this approach any

Concepts and properties of the hypothesis testing.

1. a) What is a hypothesis? Specifically, is it a statement about the population or the sample? b) What is the purpose of hypothesis testing? c) How is the role of the null hypothesis different from that of the research (alternative) hypothesis? d) Provide an example of a hypothesis test you could conduct at work

Sample proportion question

When an election for political office takes place, the television networks cancel regular programming and instead provide election coverage. When the ballots are counted, the results are reported. However, for important offices such as president or senator in large states, the networks actively compete to see which will be the f