Testing a Claim about a Standard Deviation or Variance In the FBI promotion system, last year's decoration points had a standard deviation equivalent to 7.1. This year 27 of the tested individuals had scores with a standard deviation of 4.2. Use a 0.01 significance level to test the claim that this year's testers have less va
In the 1990s, Massachusetts introduced the mandatory student testing program Massachusetts Comprehensive Assessment System (MCAS). According to the Massachusetts Department of Education, "based on 1998 MCAS test scores, all schools were placed in one of six baseline categories, Very High, High, Moderate, Low, Very Low or Critica
1. A machine is set produce tennis balls so the mean bounce is 36 inches when the ball is dropped from a platform of a certain height. The productions supervisor suspects that the mean bounce has changed and is less than 36 inches. As an experiment a sample of 12 balls was dropped from the platform and the mean height of the bou
1. The mean construction time for a standard two-car garage by Arrowhead Construction Company is 3.5 days. The time for the construction process follows the normal distribution. The construction process is modified through the use of 'precut and assembled roof trusses' rather than onsite construction of roof rafters. This should
3. You obtain the following regression statistics for the relationship between defect and volume at one of your plants. You have a random sample of results from 160 shifts at the plant. Model Summary Model R R Square Adjusted R Square Std. Error of the Estimated 1 .740 .548 .545
Salaries of postgraduates Refer to "Economics of Education Review" (Vol. 21, 2002) study of the relationship between education level and earnings, Excercise 6.31 (p. 336). A National Adult Literay Survey revealed that males with a postgraduate degree had a sample mean salary of of $61,340 (with standard error = $2,185), whil
See the attached file for clarity in the tables. 1. It is suspected that high pollution levels (measured by number of particulates found in the air) increase the levels of asthma attacks. A researcher collects data on50 people who experienced an asthma attack during the course of one year. For each person the number of part
A purchasing manager for a large university is investigating which brand of LCD projector to purchase to equip "smart" classrooms. Of major concern is the longevity of the light bulbs used in the projectors. The purchasing manager has narrowed down the choice of projector to two brands, Infocus and Proxima, and wishes to determi
As part of your work for an environmental awareness group, you want to test the claim that the mean waste generated by adults in the country is more than three pounds per person per day. In a random sample of 11 adults in the country, you find that the mean waste generated per person per day is 3.3 pounds and the standard deviat
Is there a significant difference in knowledge between on-site and off-site workers before they take the training? 2. Group Statistics Location of Work N Mean Std. Deviation Std. Error Mean Level of Knowledge BeforeTraining On-Site 30 38.10 4.866 .888 Off Site 30 38.87 5.912 1.079 Independent Samples Test Levene's
Refer to the Geographical Analysis (Oct. 2006) study of a new method for analyzing remote sensing data from satellite pixels, Exercise 6.25 (p. 335). Recall that the method uses a numerical measure of the distribution of gaps or hole sizes in the pixel, called lucanarity. Summary statistics for the lacunarity measirements in a
Suppose a random sample of 100 observers from a binomial population gives a value of p* = .63 and you wish to test the null hypothesis that the population parameter p is equal to .70 against the alternative hypothesis that p is less than .70. a) Noting that p* = .63, what does your intuition tell you? Does the value of p* ap
A sample of five measurements, randomly selected from a normally distibuted population, resulted in the following summary statistics : x = 4.8, s = 1.3 a) Test the null hypothesis that the mean of the population is 6 against the alternative hypothesis, u > 6. Use ? = .05. b) Test the null hypothesis that the mean of the p
The PGA and Golf Digest have developed the Play Golf America program, in which teaching professionals at participating golf clubs provide a free 10 minute lesson to new customers. According to Golf Digest, golf facilities that participate in the program gain, on average, $2400 in green fees, lessons, or equipment expenditures.
See attached file. Use the M&Ms data to complete this assignment. You will be using the methods of 7.4 for the color proportions and 7.2 for the mean number of candies per bag. For the Bonus you will be using the methods of 7.5. Be sure to state clear hypotheses, test statistic values, critical value or p-value, decision
13) The owner of a bottling company is considering buying a new bottling machine. He has been testing two different machines that are being considered. After collecting 300 samples from each machine over several weeks, he was able to conduct a two sample z test.<p>He decided to utilize a 0.05 significant level for the test. The
1) A hypothesis test that involves a small sample requires that we make the following assumption that A. a larger computed value of t will be needed to reject the null hypothesis B. the confidence interval will be wider than for large samples C. the region of acceptance will be wider than for large samples D.
See the attached data file. Harrigan University is a liberal arts university in the Midwest that attempts to attract the highest quality students, especially from its region of the country. It has gathered data on 178 applicants who were accepted by Harrigan. The data are in the file named Harrigan which is posted on my webs
The mean on a normally distributed geography test is 75. Julia scores +1 standard deviation on that test. The mean of a normally distributed arithmetic test is 80. Julia scores +1 standard deviation on that test, as well. On which test did Julia do better, compared with others who took those same two tests? A. She did better
Please see the attached problem. 1. Find the p-value associated with the test. 2. Construct a 95% confidence interval for this situation. Use this interval to determine whether the true mean yield has changed. Discuss the relationship of the 95% confidence interval and the corresponding hypothesis test
A soft drink filling machine, when in perfect adjustment, fills the bottles with 12 ounces of soft drink. A random sample of 25 bottles is selected, and the contents are measured. The sample yielded a mean content of 11.88 ounces, with a standard deviation of 0.24 ounces. Use a 0.05 level of significance and test to see if the
A new soft drink is being market tested. A sample of 400 individuals participated in the taste test and 80 indicated they like the taste. Using a 0.01 level of significance, test to determine if at least 22% of the population will like the new soft drink (perform all six steps of hypothesis testing, including p-values).
In order to determine whether or not a driver's education course improves the scores on a driving exam, a sample of six students were given the exam before and after taking the course. The results are shown below: Score Score Student Before the Course After the Course 1 83 87 2
The manager of Tammy Corporation wants to determine whether or not the type of work schedule for her employees has any effect on their productivity. She has selected 15 production employees at random and then randomly assigned five employees to each of the three proposed work schedules. The following table shows the units of p
Significance Level: Hypothesis testing is the basis of inferential statistics. Statisticians are always coming up with new tests and testing new characteristics of population parameters. One of the simplest tests that currently exist is the one-sample test for means. A random sample is drawn. If the population variance is
An experimental bumper was designed to reduce damage in low-speed collisions. This bumper was installed on an experimental group of vans in a large fleet, but not on a control group. At the end of a trial period, accident data showed 12 repair incidents for the experimental group and 9 repair incidents for the control group.
A hypothesis can be rejected at one significance level, but not rejected at another significant level for the same set of samples. The level of significance reflects how much error we can tolerate in the test conclusion. For example, when we buy a 4,000-square-feet house, do you think the measurement is really exact 4,000 square
A random sample of 300 beer drinkers is selected and each member of the sample is asked to choose between two brands of beers: Brand A and Brand B. The results are that 165 prefer Brand A and 135 prefer Brand B. Conduct a hypothesis test. What is the p-value, and how much evidence is there to conclude that more than 50% of
Vendall leases soft drink vending machines that are designed to dispense 10 ounces of soft drink. Customers complain when machines dispense too much soft drink, causing spillage, and customers also complain when machines dispense too little soft drink. A particular machine is being tested by a random sample of 144 soft drinks.