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Long term effects of preschool programs for poor children

To study the long term effects of preschool programs for poor children, the High/Scope Educational Research Foundation has followed two groups of Michigan children since early childhood. One group of 62 attended preschool as 3 and 4 year olds. A control group of 61 children from the same area and similar backgrounds did not at

Inference about a Population Proportion for doctor assisted suicide

A Gallup Poll asked a sample of Canadian adults if they thought the law should allow doctors to end the life of a patient who is in great pain and near death if the patient makes a request in writing. The poll included 270 people in Quebec, 221 of whom agreed that doctor assisted suicide should be allowed. (a) What is the m

Hypothesis Testing of Proportions: Two sample Z Test

A committee studying employer-employee relations proposed that each employee would rate his or her immediate supervisor and in turn the supervisor would rate each employee. To find reactions regarding the proposal, 120 office personnel and 160 plant personnel were selected at random. Seventy-eight of the office personnel and 90


7. A researcher is interested in comparing the response times of two different cab companies. Companies A and B are each called at 50 randomly selected times. The calls to the company A are made independently of the calls to company B. The response times for each call are recorded. The summary statistics are as follows Compa

Statistics: IQ comparison of older vs. younger workers

IQ comparison of older vs. younger workers. the 1967 Age Discrimination in Employment Act made it illegal to discriminate against workers 40 years of age and older. Opponents of the law argue that there are sound economic reasons why employers would not wan tto hire and train workers who are very close to retirement. They a

A study reported in "Inside Higher Education News" (May, 2006) found that financial incentives can improve low-income college students' grades and retention. As part of their "Opening Doors" program, a Louisiana community college offered to pay students $1,000 per semester on condition that they maintain at least half-time enrollment and at least a 2.0 GPA.

Financial incentives for college students. A study reported in "Inside Higher Education News" (May, 2006) found that financial incentives can improve low-income college students' grades and retention. As part of their "Opening Doors" program, a Louisiana community college offered to pay students $1,000 per semester on condi

Calculating mean, standard deviation and z-score

Please help with the following statistics problem. Provide step by step calculations for each. You learned that 27% of all small business owned by non-Hispanic whites nationwide are women-owned firms. In a random sample of 350 small businesses owned by non-Hispanic whites, let x be the number that are owned by a woman. a)

Statistics: Fast food restaurant mean waiting time and correctly filed orders

Q-4a. You are the manager of a fast food restaurant. You want to determine whether the population mean waiting time to place an order has changed in the past month from its previous population mean value of 4.5 minutes. From past experience, you can assume that the population is normally distributed with a population standard

Statistics: Analyze Student Exam Scores

Students were given an exam with 300 multiple choice questions. The distribution of the scores were normal and the mean was 195 with a standard deviation of 30. you may find it helpful to draw out this distribution before answering the questions below 16. What were the scores of the students who were within one standard devia

Statistics: 10 multiple choice questions

Find the area under the standard normal curve between z=0 and z=3. A. 0.4987 B. 0.9987 C. 0.4641 D. 0.0010 IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. An individual's IQ score is found to be 110. Find the z-score corresponding to this value. A. -1.33 B. 1.33 C. -0.67

Test the hypothesis for proportions of red and brown M&Ms.

See attached file for M&M data. Test the hypothesis (± = 0.05) that the population proportions of red and brown are equal (pred = pbrown). You are testing if their proportions are equal to one another, NOT if they are equal to one another AND equal to 13%. NOTE: These are NOT independent samples, but we will use this approac

Purpose and Use of the Z-Score

I need to explain the z-score, the purpose of it, and how it works, to an individual that has the reading and comprehensive level of a 10 year old (4th grader). Can you give me at least two examples to help him understand,

Statistics: Z-score, sample standard deviation, standardized score

1. For a population with µ=50 and σ=10, A. What is the z-score for X=55, X=60, X=75, X=45, X=30 and X=35? B. Find the X value that corresponds to each of the following z-scores, z=1.00, z=0.80, z=1.50, z= -0.50, z= -0.30 and z= -1.50. 2. Find the z-score corresponding to a score of X=60 for each of the following dis

Hypothesis Test for One Population Proportion Z test: 12.56 and 12.58

Use One-Proportion Z-Test 12.56 Christmas Presents. The Arizona Republic conducted a telephone poll of 758 Arizona adults who celebrate Christmas. The question asked was, "In your family, do you open presents on Christmas Eve or Christmas Day?" Of those surveyed, 394 said they wait until Christmas Day. a. Determine the

Statistics: Z test for population proportion

Hypothesis test for the difference of population proportions Large companies typically collect volumes of data before designing a product, not only to gain information as to whether the product should be released, but also to pinpoint which markets would be the best targets for the product. Several months ago, I was inte

Hypothesis test for the population mean: Z test for mean lifetime of light blubs

Hypothesis test for the population mean: Z test A manufacturer claims that the mean lifetime, mu, of its light bulbs is 44 months. The standard deviation of these lifetimes is 8 months. Ninety bulbs are selected at random, and their mean lifetime is found to be 43 months. Can we conclude, at the 0.05 level of significance, t

Hypothesis Testing: Two sample Z test for proportion

1.To compare the effectiveness of two treatments 1 and 2 for a particular disease. Patients were separated in 2 treatment groups. A patient in group 1 received treatment 1 and patients in group 2 received treatment 2. The results are given in the table below: Treatment 1 Treatment 2 Success 170 180 Failure 30 10 (a) To

Study to determine drinking behavior of students

The University of Arkansas conducted a study to determine the drinking behavior of their students. They looked at 2 populations, students who lived on campus versus students who did not live on campus. They want to know if there is a difference in the drinking behavior between the 2 groups (use 95% level of confidence)

Z Test of data for average GPA of students. Is GPA for biology different?

Data shows the average GPA of students at a school is 2.9. The GPA of a random sample of 16 biology students is 3.1 (with sample standard deviation= 1.2) Is the GPA of the biology students different from the general student body? Identify and justify the statistical procedure. Show all steps to test the hypothesis and in

Z test for two population proportions

A clinical trial is conducted comparing a new pain reliever for arthritis to a placebo. Participants are randomly assigned to receive the new treatment or a placebo and the outcome is pain relief within 30 minutes. Is there a significant difference in the proportions of patients reporting pain relief? Run the test at a 5% level

Z-Score and Probability

1. An industrial sewing machine uses ball bearings that are targeted to have a diameter of 0.75 inch. The lower and upper specification limits under which ball bearings can operate are 0.74 inch and 0.76 inch, respectively. Past experience has indicated that the actual diameter of the ball bearings is approximately normally di

Statistics: Report on mean amount spent for lunch in company cafeteria.

A company is interested in estimating the costs of lunch in their cafeteria. After surveying employees, the staff calculated that a 95% confidence interval for the mean amount of money spent for lunch over a period of six months is ($780, $920). Now the organization is trying to write its report and considering the following

Test and Measurements Task

See attached chart. Your assistance is greatly appreciated. Thank you. TASK You have been provided the z-scores of three individuals. 1. Person A received a z-score of 1.0. 2. Person B received a z-score of 0 3. Person C received a z-score of -1.0. Using Figure above (see attchement), indicate each individual's sco

Statistics: Grumney Family, MacBurger, National Safety Council, Chicken Delight

1. At the time she was hired as a server at the Grumney Family restaurant, Beth Brigden was told, "You can average at least $20 a day in tips." Over the first 35 days she was employed at the restaurant, the mean daily amount of her tips was $24.85, with a standard deviation of $3.24. Can Ms. Brigden be 99% confident that

Statistics: Calculate z-scores for each student's test grades

One professor teaches a large section, section A, of a particular class, and on the first test of the term, the test scores in section A were approximately normally distributed with a mean of 78 and a standard deviation of 6. Another professor also teaches a large section, section B, of the same class, and on the first test of t