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Hypothesis Testing

Hypothesis Testng: Wilcoxon Rank Sum Test

1) Two gasoline additives will be tested to determine their impact on miles per gallon for passenger cars. In the experiment, each car was tested with both gasoline additives. Use a level of significance α = 0.05 and the rank sum test Wilcoxon test whether any significant difference in the two additives.

Case Study 11.1 (Testing hypothesis)

Sample Item Original Supplier New Supplier 1 0.374 0.391 2 0.387 0.375 3 0.359 0.365 4 0.391 0.360 5 0.390 0.366 6 0.361 0.378 7 0.376 0.377 8 0.371 0.364 9 0.373 0.332 10 0.364 0.343 11 0.390 0.378 12 0.384 0.401 13 0.384 0.382 14 0.383 0.381 15 0.381 0.363 16 0.369 0.371 17 0.361 0.352 18 0.376 0.393 19 0.38

Business Research

The maker of refrigerators buys bolts from two suppliers, and it is very important that the mean widths of the bolts received from both suppliers are equal since they must be used interchangeably. The refrigerator maker receives a large shipment of volts from each supplier and draws a random sample of 49 bolts from each shipmen

Null and Alternative Hypotheses and Levels of Significance

A lab technician is tested for her consistency by taking multiple measurements of cholesterol levels from the same blood sample. The target accuracy is a variance in measurements of 1.2 or less. If the lab technician takes 16 measurements and the variance of the measurements in the sample is 2.2, does this provide enough evide

Stem Cell Transplant & Worker Motivation Problems

See attached file for data. 10.28 Multiple myeloma, or blood plasma cancer, is characterized by increased blood vessel formulation (angiogenesis) in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient's own stem cells. The fo

'Statistics for Managers' using Excel 5th edition: T F questions

True or False: The t distribution is used to develop a confidence interval estimate of the population mean when the population standard deviation is unknown. True or False: The confidence interval estimate of the population proportion is constructed around the sample proportion. True or False: The F test used for testing t

Hypothesis Testing -Number of Seniors Planning to Attend College

Results from previous studies showed 79% of all high school seniors from a certain city plan to attend college after graduation. A random sample of 200 high school seniors from this city reveals that 162 plan to attend college. Does this indicate that the percentage has increased from that of previous studies? Test at the 5%

Null and alternate hypothesis

1.A machine produces 5-inch nails. A sample of 12 nails was selected and their lengths determined. The results are as follows: 4.94 4.94 5.07 4.91 4.98 5.00 4.94 5.09 5.00 4.92 5.08 5.06 Assuming that a = 0.10, test the hypothesis that the population mean is equal to 5. ?State the null and alternate hypotheses ?&

Sample Hypothesis Testing

Objective: Identify the formal hypothesis testing process. 1. If a null hypothesis is not rejected at the 0.10 level, it may be rejected at the 0.05 level. a. 0 True b. 0 False Objective: Perform a hypothesis test of one proportion. 2. The Roman Senate has become concerned about the loyalty of the army in Gaul com

Hypothesis Testing problem

A machine produces 5-inch nails. A sample of 12 nails was selected and their lengths determined. The results are as follows: 4.85 4.80 4.89 4.82 4.94 4.96 4.96 4.83 4.80 4.84 4.95 4.88 Assuming that = 0.10, test the hypothesis that the population mean is equal to 5. · State the null and alternate hypothe

F-test and confidence interval

Consider the following Hypothesis Testing: H0: δ1² = δ2² Ha: δ1² ≠ δ2² The sample size for sample 1 is 25, and for sample 2 are 21. The variance for sample 1 is 4.0 and for sample 2 is 8.2 a) at the confidence level of 0.98, what is your conclusion of this test? b) What is the confidence

Critical value/ p-value

The owner of a restaurant has just changed the delivery process in order to reduce the mean time between the order and completion of delivery from the current 25 minutes. In the past, the population standard deviation has been 6 minutes. A sample of 36 orders under the new delivery process results in a sample mean of 22.4 minu

Raw Data

Directions: Use the attached set of raw data to complete the following tasks. For tasks 1 through 4 please focus on New Mexico highway fatalities.. In task five you will be comparing New Mexico and U..S. highway fatalities. All work must be done by hand. You may use a calculator but only as an aid.. You must demonstrate tha

Hypothesis Testing of Variance & Sample size

Question 5 Use the traditional method to test the given hypothesis. Assume that the population is normally distributed and that the sample has been randomly selected A machine dispenses a liquid drug into bottles in such a way that the standard deviation of the contents is 81 milliliters. A new machine is tested on a sample

Statistics: Test Grocery store self checkout systems

Many grocery stores have installed self checkout systems. Below is the number of customers using the service for a sample of 15 days at the Wal-Mart in Boonton, 120 108 120 114 118 91 118 92 104 104 105 112 97 118 108 117 Is it reasonable to assume that the mean number of customers using self che


Use n=25 for each problem where necessary. An accountant randomly selects (60+n) general accounts payable and examines them to determine whether they are correct. Six accounts contained errors. Construct a 98% confidence interval for the true proportion of general accounts payable that contain errors. Com

Minitab project

Please see the attachment. Instructions: ? Follow the directions for each problem. ? Use Minitab for all the calculations. ? The data set is available in contents page of D2L in the Final Exam module called fall 2009.MTW. ? Label each printout of your Minitab session according to the problem and part of that problem.

Dependent & Independent Variables, Hypothesis

NClinics, Inc. is a specialty e-tailer that sales clothing and accessories for nurses and operates 87 catalog Web sites on the Internet. Kevin Conn, Sales Director, feels that the style (color scheme, graphics, fonts, etc.) of a Web site may affect its sales. He chooses three levels of design style (neon, old world and sophist

Hypothesis Testing: Mean cost of raising a child

The US Department of Agriculture reports that the mean cost of raising a child from birth to age 2 in a rural area is $8,390. You believe that this value is incorrect, so you select a random sample of 900 children (age 2) and find that the mean cost is $8,275 with a standard deviation of $1,540. At α = 0.05, is there enough

Likelihood of Fraud in a Furniture Retailer Fire

See attached data file. A wholesale furniture retailer stores in-stock items at a large warehouse located in Tampa, Florida. In early 1992, a fire destroyed the warehouse and all the furniture in it. After determining the fire was an accident, the retailer sought to recover costs by submitting a claim to its insurance company

Hypothesis Testing & Confidence Interval: yield of corn

Bushels of Corn Crop researchers plant 15 plots with a new variety of corn. The yields in bushels per acre are: 138.0 139.1 113.0 132.5 140.7 109.7 118.9 134.8 109.6 127.3 115.6 130.4 130.2 111.7 105.5 Assume that the standard deviation of the population is known to be σ = 10 bushels per acre QUESTIONS: 1. Wh

Statistics: test whether relaxation training affect number of chronic headaches?

A researcher would like to determine if relaxation training will affect the number of headaches for chronic headache sufferers. For a week prior to training, each participant records the number of headaches suffered. Participants then receive relaxation training, and for the week following training the number of headaches is aga

Elementary Statistics for Null and Alternative Hypothesis

Elementary Statistics 1. A researcher knows that the population mean among college students taking the social test is a "neutral" 100. (scores higher than 100are assumed to represent more conformity than average and those lower than 100 indicates less conformity). A random sample of 30 students was selected, and the followin

Statistics: Multiple Regression for a Data Set

See file attached. Using the Major League Baseball Data Set available through the "Data Sets" link on your page, answer the research question of whether the number of wins of a team can be explained linearly by The Size of Stadium, ERA, and Stolen Bases. What I need to do is describe and perform multiple regression

Hypothesis Testing Questions: T-Test and ANOVA

1. What does it mean practically when we say that we found a significant difference between two groups using a t-test? 2. Describe a business situation where you would want to use a t-test. Why would you choose that test? What would you expect to show by doing this? 3. Describe a business situation where you would wan