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    Hypothesis Testing

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    Hypothesis Test: Critical Value

    Suppose that a company claims that their mean weekly sales are $12,250. A random sample 35 weeks yields a sample mean of with a sample standard deviation of s=$1250. H0: m = 12,250 H1: m # 12,250 Find the critical values for the hypothesis test. Assume that the significance level is a=0.05. Answer: ______________

    Inference of population mean: Changing electrical field from natural level slows healing Is there good evidence that changing the electrical field from its natural level slows healing?

    Inference of population mean: Changing electrical field from natural level slows healing Our bodies have a natural electrical field that is known to help wounds heal. Does changing the field strength slow healing? A series of experiments with newts investigated this question. The data below are the healing rates of cuts (m

    Determining Null and Alternative Hypotheses

    The mean height of a certain kind of plant is 125 centimeters. Suppose we want to carry out a hypothesis test to see if the mean height when these plants are treated with a certain chemical differs from 125 . State the null hypothesis H0 and the alternative hypothesis H1 that we would use for this test.

    Number of bottles and the probability of each number

    Please see the attached file for full problem description. 1. Given the number of bottles (0,1,2,3,4) and the probability of each number being overfilled in one month, what is the expected number of overfilled bottles per month? E(X) = SUM(x*P(x)) 2. Given n=4 & p=.3 for a binomial experiment, the

    3 Statistics Problems

    1. Which hypothesis testing model would be used under each of the following conditions. Use the "model number" from my handout if you wish. By line the information given in each cell is: Level of measurement, number of groups, sample size to be taken, parameter of interest and any qualifications. [Please refer to the attachme

    Hypothesis Testing: Legal Services & Sentence Satisfaction

    See attached data set. Using AIU's survey responses from the AIU data set, complete the following requirements in the form of a report: Perform a two-tailed hypothesis test on both the legal services satisfaction and the sentence satisfaction variable's data using a .05 significance level. Begin by creating a null and a

    Testing a null hypothesis at a .05 level of significance

    Assume that it is well established that the average number of correctly recalled items from a 50 item word list is 22 words. A cognitive psychologist is interested in knowing if a new mnemonic training program will improve recall on a 50 item word list. She gives the mnemonic program to 16 students and then tests their recall

    Standard deviation

    An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean out-of-pocket patient billing above the reimbursed amount was $275.66 with a standard deviation of $78.11. (a) At the 5 percent level of significance, does this sample prove a violation of the guideline that the

    P-value

    A coin was flipped 60 times and came up heads 38 times. (a) At the .10 level of significance, is the coin biased toward heads? Show your decision rule and calculations. (b) Calculate a p-value and interpret it.

    Mean, p-value

    Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard devi

    Hypothesis Test

    A manufacturer is interested in determining whether it can claim that the boxes of detergent it sells contain, on average, more than 500 grams of detergent. From past experience the manufacturer knows that the amount of detergent in the boxes is approximately normally distributed. The firm selects a random sample of 100 boxes an

    Hypothesis testing: U.S. Navy example

    A U.S. Navy recruiting center knows from past experience that the heights of its recruits are normally distributed with mean 68 inches. The recruiting center wants to test the claim that the average height of this year's recruits is greater than 68 inches. To do this, recruiting personnel take a random sample of 64 recruits from

    Walking and weight loss

    A study of employees at a large company found a negative correlation between weight and distance walked on an average day. In other words, people who walked more weighed less. Would you conclude that walking causes lower weight? Can you think of an alternate explanation for the findings? This responses should be 200 words

    Performance of First Grade Students vs. National Norm

    In comparing the performance of first-grade students in his district with the national norm of 100 on a widely used IQ test, the results for a random sample of his first graders lead him to retain Ho: ? = 100 (? = .01) for his population. He concludes, 'My research proves that the average first grader in our district falls right

    Method process for null hypothesis

    Be sure to clearly state your decision on the null hypothesis 1: 9:31: At Oxnard University, a sample of 25 senior accounting majors showed a mean cumulative GPA of 3.25 with a standard deviation of 0.10. At α = .05 in a two-tailed test, does this differ significantly from 3.20 (the mean GPA for all business school sen

    Hypothesis Testing of Variances: Concession Stand Purchases

    A sample of 25 concession stand purchases at the October 22 matinee of Bride of Chucky showed a mean purchase of $5.29 with a standard deviation of $3.02. For the October 26 evening showing of the same movie, for a sample of 25 purchases the mean was $5.12 with a standard deviation of $2.14. The means appear to be very close, bu

    Test the hypothesis that students who finish an exam first get a better grade.

    To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in. The first 25 papers showed a mean score of 77.1 with a standard deviation of 19.6, while the last 24 papers handed in showed a mean score of 69.3 with a standard deviation of

    10.44 Test whether Lovastatin reduce the risk of heart attack

    Does Lovastatin (a cholesterol-lowering drug) reduce the risk of heart attack? In a Texas study, researchers gave Lovastatin to 2,325 people and an inactive substitute to 2,081 people (average age 58). After 5 years, 57 of the Lovastatin group had suffered a heart attack, compared with 97 for the inactive pill. (a) State the

    Hypothesis Test

    The Web-based company Oh Baby! Gifts has a goal of processing 95 percent of its orders on the same day they are received. If 485 out of the next 500 orders are processed on the same day, would this prove that they are exceeding their goal, using alpha = 0.025?

    Hypothesis Test

    Faced with rising fax costs, a firm issued a guideline that transmissions of 10 pages or more should be sent by 2-day mail instead. Exceptions are allowed, but they want the average to be 10 or below. The firm examined 35 randomly chosen fax transmissions during the next year, yielding a sample mean of 14.44 with a standard devi

    Test significance of stock returns for companies

    See data file attached. During the last decade, a number of institutions dedicated to improving the quality of products and services in the United States have been formed. Many of these groups annually give awards to companies that produce high quality goods and services. An investor believes that publicly traded compan

    Test Surveys of Customers for Red Lobster Restaurant

    The Red Lobster Restaurant chain regularly surveys its customers. On the basis of these surveys, the management of the chain claims that 75% of its customers rate the food as excellent. A consumer testing service wants to examine the claim by asking 460 customers to rate the food. What is the probability that less than 70% of

    Difference Between the Null and Alternate Hypothesis

    Explain the difference between the null hypothesis and the alternate hypothesis. How is the null hypothesis chosen? Why is it null? What is the importance of rejecting the null hypothesis in relation of the sample to the population? With a failure to reject the null hypothesis, might we make a general statement about the populat

    Difference Between a Left-Tailed, Two-Tailed & Right-Tailed Test

    Explain the difference between a left-tailed, two-tailed, and right-tailed test. When would you choose a two-tailed test? How might you tell the direction of the test by looking at a pair of hypothesis? How might you tell which direction (or no direction) to make the hypothesis by looking at the problem statement (research quest

    Hypothesis Testing: Male Driver Example

    A psychologist believes that at least 80 percent of male drivers, when lost, continue to drive hoping to find the location they seek rather than ask for directions. To test this belief, she took a random sample of 400 male drivers and asked each what they did when lost. Of these drivers, 309 indicated that they do not ask for

    Mean Aluminun Content, Promotion Code Stamps, Weight Bearing

    See attached file for questions and data. AluminiCorp is a major producer of aluminum cans that produces 40 billion aluminum cans every year. You work as a quality control officer for AluminiCorp, and are responsible for ensuring that the aluminum cans produced meet certain specifications. Each can is supposed to consist of p

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