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    Hypothesis Testing

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    Checking for Pollution

    A common method of checking for pollution in a river is to measure the dissolved oxygen content in the river water at different locations. A reduction of oxygen content in the water from one location to another indicates the presence of pollution somewhere between the two locations. The Environmental Protection Agency (EPA) su

    Gasoline Additive

    To learn about the effect of a newly developed gasoline additive on gas mileage (mpg), seven cars were driven 300 miles first without additive and then 300 miles with a gas additive. Here are the mpg's. Did the new additive improve gas mileage? Also, is the test dependent or independent. Car # m

    Null and Alternative Hypothesis Statement

    To increase rainfall, extensive cloud-seeding experiments are to be conducted, and the results are to be compared with a baseline figure of .54 inch of rainfall ( for comparable periods when cloud seeding wasn't done). Set up the hypothesis only and decide if you have a 2 tail, 1 tail upper, or 1 tail lower test.

    Mean Number of Hours Spent in Industry per Week

    The manager of a computer software company wishes to study the number of hours senior executives spend at their desktop computers by type of industry. The manager selected a sample of five executives from each of three industries. At the .05 significance level, can she conclude there is a difference in the mean number of hours s

    Hypothesis Testing: Minor Automobile Accidents

    A number of minor automobile accidents occur at various high-risk intersections in Teton County despite traffic lights. The Traffic Department claims that a modification in the type of light will reduce these accidents. The county commissioners have agreed to a proposed experiment. Eight intersections were chosen at random, and

    The Grand Strand Family Medical Center

    The Grand Strand Family Medical Center is specifically set up to treat minor medical emergencies for visitors to the Myrtle Beach area. There are two facilities, one in the Little River Area and the other in Murrells Inlet. The Quality Assurance Department wishes to compare the mean waiting time for patients at the two locations

    White Industries

    The management of White Industries is considering a new method of assembling its golf cart. The present method requires 42.3 minutes, on the average, to assemble a cart. The mean assembly time for a random sample of 24 carts, using the new method, was 40.6 minutes, and the standard deviation of the sample was 2.7 minutes. Using

    MacBurger Restaurant Chain

    The MacBurger restaurant chain claims that the waiting time of customers for service is normally distributed, with a mean of 3 minutes and a standard deviation of 1 minute. The quality-assurance department found in a sample of 50 customers at the Warren Road MacBurger that the mean waiting time was 2.75 minutes. At the .05 signi

    Yules coefficient and interpretation

    7. There is a program for STD/HIV/pregnancy education/prevention called Postponing Sexual Involvement (PSI) run in Atlanta. Evaluation data collected at the end of ninth grade as a follow-up to the program compared two group of adolescents - one treatment and one control - all of whom had not had sex at the pretest (beginning o

    Research Design

    1. The Dean is hanging his head in shame. He realizes his failings in designing an adequate research design to assess the effects of the move on majors and has revised the proposal. Unfortunately, the word processor used (WordImperfect) has scrambled the text and he needs help in correcting the text. In the paragraphs below, h

    Hypothesis Test of variance

    The following hypothesis are given. H0: σ2/1 ≤ σ2/2 H1: σ2/1 > σ2/2 A random sample of five observations from the first population resulted in a standard deviation of 12. A random sample of seven observations from the second population showed a standard deviation of 7. At the .01 significance level

    Two Statistics Problems

    (See attached file for full problem description) --- 1. On a college bulletin, it is stated that the weights of the male students are normally distributed with mean = 165lb and a standard deviation = 16lb. A research student decided to verify the claim of the school by taking a sample of 64 students. The average weight of the

    A recent article in the Cincinnati Enquirer...

    10. A recent article in the Cincinnati Enquirer reported that the mean labor cost to repair a heat pump is $90 with a standard deviation of $22. Monte's Plumbing and Heating Service completed repairs on two heat pumps this morning. The labor cost for the first was $75 and it was $100 for the second. Compute z values for each and

    Null hypotheses again

    Of all the presidents since WWII, Jimmy Carter suffered the worst overall approval rating at 45%. George W. Bush's approval rating varied widely. It reached a high of 90% just after 9/11, but in mid-July, it stood at 49% as measured by CNN/USA Today/Gallup poll of 1000 randomly selected adults. Is there evidence to suggest that

    Values of test statistics

    The following sample data were obtained from three populations where the variances were not equal, and you wish to compare the populations. Sample 1 Sample 2 Sample 3 21 15 38 29 17 40 35 22 44 45 27 51 56 31

    Decision Rules, Test Statistics, and Null Hypothesis

    H-subzero: Pie = .40 H-subone: Pie does not equal .40 A sample of 120 observations revealed that p = .30. At the .05 significance level, can the null hypothesis be rejected? A: State the decision rule B: Compute the value of the test statistic C: What is your decision regarding the null hypothesis?

    Hypothesis testing and correlation coefficient

    1. A normal tomato will gain an average of 2 ounces per week during the growing season. A sample of 100 tomatoes is given a special hormone to increase their growth. The average weight gain of tomatoes in the sample was 3 ounces with a standard deviation of 1 ounce. Conduct a hypothesis test to determine if the hormone increased

    Hypotheses testing example problem

    A normal tomato will gain an average of 2 ounces per week during the growing season. A sample of 100 tomatoes is given a special hormone to increase their growth. The average weight gain of tomatoes in the sample was 3 ounces with a standard deviation of 1 ounce. Conduct a hypothesis test to determine if the hormone increased

    Decision Rules, Computing Values, and Making Decisions

    H-sub zero: pie = .40 H-sub one: pie does not equal .40 A sample of 120 observations revealed that p=.30. At teh .05 significance level, can the null hypothesis be rejected? A- State the decision rule B- Compute the value of the test statistic. C- What is your decision regarding the null hypothesis?

    Hypothesis & Confidence Statement

    Identical surveys were conducted in 1990 and 2000. One question asked women was "Are most men basically kind, gentle, and thoughtful. The 1990 survey revaled that of the 3000 women surveyed, 2010 said they were. The 2000 survey revealed 1530 of 3000 thought they were. At the .05 level, can we conclude that women think men ar

    2 Problems

    2) Disney tells you that the average distance between the ears on a Mickey Mouse hat is 5 inches. In a sample of 100 Mickey Mouse hats you find that the average distance between the ears on the hats is 5.2 inches with a standard deviation of 1 inch. Conduct a hypothesis test to determine if the average distance between the ear

    Hypothesis Testing, Null and Alternate Hypothesis and Two-Tailed Hypothesis Tests

    5) ESPN reported in sample of 1000 homes the proportion of people who watched the Texas v. Ohio State college football game this weekend was .6. ESPN also reported that in another sample of 1000 homes the proportion of people who watched the Arizona State v. Louisiana State game was .4. Conduct a hypothesis test to determine i

    Nonparametric Methods-Frequency Distributions

    A six-sided die is rolled 30 times and the numbers 1 through 6 appear as shown in the following frequency distribution. At the .10 significance level, can we conclude that the die is fair? (Please see attached for data).