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Analysis of Variance

Hypothesis Testing: Three Categories

1. Group the districts based on the percent of students on welfare: "low" (less than 5 percent), "moderate" (5 up to 10 percent), and "high" (10 percent or more). Conduct a test of hypothesis to determine whether the three categories are equally represented in the sample. Use the .05 significance level. 2. Identify each distr

ANOVA to determine the effectiveness of fore training programs

#4.2 The personnel manager of a large finance company wished to evaluate the effectiveness of 4 different sales-training programs designed for new employees. A group of 32 recently hired employees are randomly assigned to the 4 training programs so that there are 8 subjects in each program. At the end of the program an exam i

ANOVA One Factor Experiments - One way Classification

An experiment is performed to determine the yields of 5 different varieties of wheat, A, B, C, D, E. Four plots of land are assigned to each variety, and the yields (in bushels per acre) are as shown in table. Assuming the plots to be of similar fertility and that varieties are assigned at random to plots, determine if there is

Fathers recorded how many minutes per day they played with their child for 5 days. This data file contains 60 cases and three variables; a factor indicating the disability status of the child, a factor indicating the child?s gender, and a play time score averaged across 5 days.

Fathers recorded how many minutes per day they played with their child for 5 days. This data file contains 60 cases and three variables; a factor indicating the disability status of the child, a factor indicating the child?s gender, and a play time score averaged across 5 days. 5. Conduct a two-way ANOVA to evaluate differen

ANOVA from output table

ANOVA: Single Factor SUMMARY Groups Count Sum Average Variance Column 1 70 29296 418.5143 2069.732 Column 2 66 26720 404.8485 1274.254 Column 3 73 29468 403.6712 938.696 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 9546.877 2 4773.438 3.353505 0.036881


A DRUG IS DEVELOPED TO LOWER PULSE RATES. In order to obtain more consistent results that do not have confounding variables of gender, the drug is tested using males only. Given below are pulse rates for a placebo group, a group of men treated with Xynamine in 10 mg doses and a group of men treated with 20mg doses. Research find

Analysis Tool

1. We wish to analyze the results from a study which involved the following steps: A random sample of 500 participants was recruited for the study ? Subjects were allowed to elect to participate in an 3-month exercise program or serve as a control subject (190 chose the program, 310 chose to serve as controls) ? Subjects wer

Variance for two-way ANOVA

What is the formula used to compute variance when performing a two-way anova? Ex: Count 2 2 4 Sum 32 34 66 Average 16 17 16.5 Variance 72 18 30.33333333

Clarification of Analysis of Variance

There are four auto body shops in a community and they all claim to promptly serve customers. To check if there is any difference in service, customers are randomly selected from each repair shop and their waiting times in days are recorded. The output from a statistical software package is: Summary Groups..........Count...

Equality of variance and ANOVA

3. It is desired to determine whether there is less variability in the silver plating done by Company 1 than in that done by Company 2. If independent random samples of size 13 of the two companies? work yield s1 = 0.062 mil and s2 = 0.035 mil, test the null hypothesis ?sigma?1squared = ?sigma?2squared against the alternative hy

One ANOVA with eta and Tukey HSD.

Suppose that you are interested in determining the effectiveness of an intensive supervision probation (ISP) program. To examine its effectiveness, you keep track of 12 offenders sentenced to ISP for one year and tabulate the number of new offenses they committed. You also gather two control groups. The first consists of 12 offe

Making an ANOVA table.

What are the calculations involved in making an ANOVA table (F test) by hand? How do you do an ANOVA by hand?

ANOVA for Flammability tests in Minitab

Flammability tests were conducted on children's sleepwear The Vertical Semirestrained Test was used, in which pieces of fabric were burned under controlled conditions. After the burning stopped, the length of the charred portion was measured and recorded. The same fabric samples were tested at five different laboratories. Th

Weights of poplar trees

This problem uses the weights of poplar trees for Year 1 and Site 1. If we use the weights for Year 2 and site 1, the analysis of variance results are shown above. Assume we want to use a 0.05 significance level in testing the null hypothesis that the four treatments result in weights with the same population mean. See a


Need to perform an ANOVA on the data below using any method of computation or anything close to an ANOVA that looks like an attempt at it. I will outline some of the issues in the medical field which has had a negative effect on patient's satisfaction and the quality of care administered by hospital or other health care fa

ANOVA and Hypothesis

An employment agency wants to see which of three types of advertisements in the help-wanted section of local newspapers is the most effective. Three types of advertisements (big headline, straightforward, and bold print) were randomly alternated over a period of weeks and the number of people responding to the advertisements was

Determine the Mean as Director of Sales

This week, as Director of Sales for your company, you must determine if the mean prices of four different suppliers are the same. Since prices vary throughout the year, you feel it necessary to take into account the month in which the price quote was given. You should also consider the size of your order. Your newly hired resear

The tensile strengths (in psi) of three types of wires are under study.

The tensile strengths (in psi) of three types of wires are under study. Suppose that following table represents the data for the three types of wires (after subtracting from the specified target value) tested. TYPE I: 11, 12, 12, 13, 10 TYPE II: 13, 14, 15, 15, 17 TYPE III: 14, 13, 15, 13, 11 (a) Perform an analysis of v

Two way ANOVA with interaction in STATDISK

I. Set up the following null and alternative hypotheses for both factors and their interaction. You should have three verbal statements, not symbolized statements. [Introductory paragraph, introduce the problem, the data and verbally describe the set-up and tests being conducted.] II. Problem: The following data contains ta

Conduct an F-test to test the hypothesis

Your company is deciding which of four machines to purchase for a production line. The machines are all designed to fill and close bottles of liquid detergent. Each machine is tested for the same period of time on 10 separate occasions in a completely randomized design. See attached file for full problem description. 1

Treatments, Variance Components

An occupational health study was carried out to evaluate the health status of workers. The response is forced expiratory volume (FEV), a measure of respiratory function. Observations are made on n=12 individuals in each of three plants where workers are exposed primarily to one of three toxic substances, depending on the section

ANOVA multiple choice questions

An operations analyst collected data on the number of acceptable units produced from equal amounts of raw material by 24 entry-level piece work employees who had received special training.Four training levels were used (6, 8, 10, and 12 hours) with 6 employees randomly assigned to each level. The resulting means and ANOVA table

ANOVA: test designed to measure perfectionism

The personnel director of Cander Machine Products is investigating perfectionism on the job. A test designed to measure perfectionism was administered to a random sample of 18 employees. The scores ranged from 20 to about 40. One of the facets of the study involved the early background of each employee. Did the employee come f


22. Random samples of five were selected from each of three populations. The sum of squares total was 100. The sum of squares due to the treatment was 40. a. What is the null hypothesis and the alternate hypothesis? b. What is the decision rule? (Use the 0.05 level of significance) c. Complete the ANOVA table. d. What is yo

Statistics LSD Excercise

A well know automotive magazine took three top of the line midsize automobiles manufactured in the United States, test drove them, and compared them on a variety of criteria. In the are of gasoline mileage performance, five automobiles of each brand were each test driven 500 miles; The miles per gallon data obtained are shown i