Statistics Worksheet Calculating Z-Scores

A standard type of problem in basic statistics is to calculate the z-score of a value, given that the data is normally distributed and also given the mean and standard deviation. This z-score, or standard score, is the signed number of standard deviations by which the data points value is above the mean value of that which is being measured. Calculating z-scores for normal distribution in statistical analysis allows one to simplify observations of normal distributions, starting with an infinite number of distributions and working down to a standard normal deviation instead of working with each application that is encountered. All of the following problems use the z-score formula, and for all of them assume that we are dealing with a normal distribution. The Z-Score Formula The formula for calculating the z-score of any particular data set is z (x -  ÃŽ ¼) /  ÃÆ' where  ÃŽ ¼Ã‚  is the mean of a population and  ÃÆ'  is the standard deviation of a population. The absolute value of z represents the z-score of the population, the distance between the raw score and population mean in units of standard deviation. Its important to remember that this formula relies not on the sample mean or deviation but on the population mean and the population standard deviation, meaning that a statistical sampling of data cannot be drawn from the population parameters, rather it must be calculated based on the entire data set. However, it is rare that every individual in a population can be examined, so in cases where it is impossible to calculate this measurement of every population member, a statistical sampling may be used in order to help calculate the z-score. Sample Questions Practice using the z-score formula with these seven questions: Scores on a history test have an average of 80 with a standard deviation of 6. What is the z-score for a student who earned a 75 on the test?The weight of chocolate bars from a particular chocolate factory has a mean of 8 ounces with a standard deviation of .1 ounce. What is the z-score corresponding to a weight of 8.17 ounces?Books in the library are found to have an average length of 350 pages with a standard deviation of 100 pages. What is the z-score corresponding to a book of length 80 pages?The temperature is recorded at 60 airports in a region. The average temperature is 67 degrees Fahrenheit with a standard deviation of 5 degrees. What is the z-score for a temperature of 68 degrees?A group of friends compares what they received while trick or treating. They find that the average number of pieces of candy received is 43, with a standard deviation of 2. What is the z-score corresponding to 20 pieces of candy?The mean growth of the thickness of trees in a forest is found to be . 5 cm/year with a standard deviation of .1 cm/year. What is the z-score corresponding to 1 cm/year?A particular leg bone for dinosaur fossils has a mean length of 5 feet with a standard deviation of 3 inches. What is the z-score that corresponds to a length of 62 inches? Answers for Sample Questions Check your calculations with the following solutions. Remember that the process for all of these problems is similar in that you must subtract the mean from the given value then divide by the standard deviation: The  z-score of (75 - 80)/6 and is equal to -0.833.The  z-score for this problem is (8.17 - 8)/.1 and is equal to 1.7.The  z-score for this problem is (80 - 350)/100 and is equal to -2.7.Here the number of airports is information that is not necessary to solve the problem. The  z-score for this problem is (68-67)/5 and is equal to 0.2.The  z-score for this problem is (20 - 43)/2 and equal to -11.5.The  z-score for this problem is (1 - .5)/.1 and equal to 5.Here we need to be careful that all of the units we are using are the same. There will not be as many conversions if we do our calculations with inches. Since there are 12 inches in a foot, five feet corresponds to 60 inches. The  z-score for this problem is (62 - 60)/3 and is equal to .667. If you have answered all of these questions correctly, congratulations! Youve fully grasped the concept of calculating z-score to find the value of standard deviation in a given data set!

The E Commerce And Online Auctions Essay - 962 Words

Market Analysis The E-Commerce and Online Auctions industry has exploded over the past decade. Lured by the ease of ordering at home and ability to quickly compare prices and product reviews among retailers, many consumers are increasingly choosing to shop online over purchasing products at brick-and-mortar locations or via mail-order catalogs. RunWayMe will be part of the growing trend with a unique concept of selling the latest celebrities look-a-like outfits at affordable prices. Although this concept has being shown in magazines, such as Instyle and People Magazine, there are no store that exclusively sell an entire outfit. In addition, RunWayMe will offer single items such as: tops, bottoms, dresses, and blazer. Target Market The conventional wisdom is that women drive shopping trends, since they control up to 80% of household spending. Fifty-seven percent of women made a purchase online in 2013. To be more specific, RunWayMe’s target market is millennials women(clothing sizes 0-8, footwear sizes 5-10), those consumers aged 20 to 34, remain the key age demographic for online commerce, spending more money online in a given year than any other age group.They spend around $2,000 annually to purchase 64 garments. This, despite having lower incomes than older adults, they dominate 21% of online clothes shopping market. With 5% of 21% RunWayMe can be successful. Also it projected that, in any given six month period, more than half of shoppers who make an online purchase willShow MoreRelatedE Commerce And Online Auctions2159 Words   |  9 PagesThreat of New Entrants The e-commerce and online auctions industry is highly fragmented, with a large number of independent players occupying 78.2% of the market. With a low concentration, the two major players, Amazon and eBay, account for only 21.8% of the e-commerce and online auctions market. 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Foreign Studies free essay sample

The terms monitoring system, topics and indicators have more emphasis in the discussions, as these concepts form the core of the study. Monitoring system What is a monitoring system? What is the purpose Of a monitoring system? What are the different structures orientations and/or classifications of a monitoring system? What factors should be considered in designing in a monitoring system for trainings? The subsequent discussions will answer these questions leading to a thorough understanding on the subject. What is monitoring system?According to Letdown, Aitkin and Janis (2001), a monitoring system Is fined as a concise description of what should be (objectives) and a process to determine to what is (procedural and status report). It is further explained that it is a framework within which to select or define, interpret and use a wide array of indicators. On a similar ground, Fit Gibbon (1996) cites that monitoring is a way of examining quality of performance, largely by the use of p erformance indicators not only regularly collected but also being reported back to the units responsible. This definition often concepts such as performance, outcomes and feedback. Greasy and Callaghan (1996) also consider monitoring as systematic and regular procedures for the repeated collection and interpretation of assessment data of important aspects of the subject under study. It is not necessarily restricted to outcome variables, but can also involve contextual information and measures of inputs and processes (House and Tijuana, 1994; and screens et al. , 1988).After considering the abovementioned definitions, it can be summarized that the monitoring system may be referred to as a strategy used to periodically track quality by recording inputs, processes, outputs and outcomes for purposes and trainings programs. Results of the monitoring system must also be fed back to all concerned units within the organization. A monitoring system encompasses a number of relevant indicators and sub- indicators, the standards by which quality measurements are based from, and the data gathering instruments of the subject being monitored.Integrated in theses definitions are the purposes of monitoring to organizations. The use of indicators will be discussed in the later part of this chapter. What is the purpose of a monitoring system? When relating to trainings, a monitoring system serves as a mechanism that revises a user or number of users with several sources of information pertaining to the process being investigated, providing feedback and signaling and diagnosing problems (Jansen, 1996);.Identify problem areas in determining the best allocation of resources; and motivate and create awareness among administrators and trainers to improve quality and stimulate self-regulatory mechanisms (Willis,1 992). It is also used to diagnose deviations from policy, determine organizational strengths and weaknesses in accomplishing specific goals, and then launch remedial actions. What are the most- common classifications of monitoring systems? Basically, this study adopts at least two classifications of moon tutoring systems according to purpose and stages.Willis (1992) classified monitoring systems for t rainings according to purpose expressed in the forms of compliance, performance and diagnostic monitoring systems. First, compliance, compliances monitoring is that if Organizations meet their standards On various measures, adequate levels Of performance will follow. For instance, in order for a manufacturing company to be ISO certified, it needs to make sure that their employees are given the sight trainings to arrive at a target performance level in compliance with the standards.Also in most government institutions, there are provisions on the continuing education and skills enhancement of employees. Institutions are being monitored whether they have satisfied trainings requirements pending the release of their annual budgets. Second, performance monitoring measures the significant change in performance or outcomes of any given intervention. Sales In particular, performance monitoring is used to observe the increase in performance after sales personnel were subjected to a series Of trainings and workshops.On way of conducting performance monitoring system emphasizes the identification of the strengths and weak nesses of a training intervention. Importance of attendance Government officials, teachers groups, and individual parents all have voic ed their concerns over the need to develop policies and practices to counteract the problems facing our nations schools today such as the dropout rate, drug abuse, and declining education performance (Bernstein, 1990). Poor school attendance arouses strong feelings in teachers, parents, members of the educational support services, educational administrators, politicians, and pupils.These strong feelings are expressed in different and often contradictory ways, depending on the individuals own perspective (Galloway, 1985). The statistics related to school absenteeism are staggering. Each school day, 2,500,000 students are reported absent from school. The dropout rate is estimated at 27 percent nationally and over 45 percent in some cities. The 27 percent dropout rate equates to 65 busloads of students who leave United States schools each week and do not return. In a years time, 700,000 students will be lost. In two years, the number will exceed one lion (Person, 1990). The Virginia Department of Education has created a system for better and more accountable schools through what is now called the Outcome Accountability Project (POP). This program establishes the criteria for how schools and school divisions will be held accountable for meeting the commitment of improving learning for all. The data from the POP provides a framework for analyzing the school district by breaking the whole into some of its parts.The attendance data for secondary students provided by the POP for the State of Virginia indicates that 66 percent of students in readers 9-12 during the school year 95-96 were absent 10 days or less from school. The POP data further lists Newport News Public Schools as having 55 percent of its grades 9-12 students absent 10 days or less from school (POP Report, 1997). The school philosophy, in general, is one that stresses to teachers, pupils, and parents the importance of regular sc hool attendance. This is because it is the belief that only through regular school attendance can students progress academically at a successful rate (Jet Plat, 1979). Attendance is part of a pupils cumulative record. It is important that good school attendance habits be established for later years when pupils seek employment (Jet Plat, 1979). Jet and Plat conclude that attendance and its importance should be taught to students. Basic to that philosophy is the belief that poor student attendance and truancy are some of the first signs of decay of a school and school system.Therefore, it is incumbent upon educators to do all they can to promote good school attendance habits among their pupils. Anyone who has skipped or had to repeat a grade, has been placed in or excluded from a special program, or as been denied academic credit because of absences knows the importance of local school policies. While scholarly attention has tended to focus on federal and state education policy, those who attend and work in schools realize that their lives can be affected greatly by policy made at the school and district level (Duke and Canada, 1 991 Cuba (1984) identifies eight distinct conceptions of policy.They include the following: policy is an assertion of intents or goals. Policy is the accumulated standing decisions of a governing body, by which it regulates, controls, promotes, services, and otherwise influences matters within its peer Of authority. Policy is guide to discretionary action. Policy is a strategy undertaken to solve or ameliorate a problem. Policy is sanctioned behavior. Policy is a norm of conduct characterized by consistency and regularity in some substantive action area. Policy is the output of the policy-making system.Policy is the effect of the policy-making and policy-implementing system as it is explained by the client. The researcher believes that each of the above conceptions by Cud has some value for the study of school district and school policy. Duke and Canada (1991) refer to school policy as NY official action taken at the district or school level for the purpose of encouraging or requiring consistency and regularity. They further state that the definition implies intentionality on the part of those developing policy.Pizza (1983) refers to school policy as fitting into an ecology of public policies. In other words, where the operation of pubic schools is concerned, a range of policy sources can be identified. Pizza further states that policies are derived from Congress, the Department Of Education, the courts, State legislatures, intermediate agencies, school boards, and school-based personnel. To understand educational policy in the United States, it is necessary to understand each of these policymaking entities and the relationships among them. Duke and Canada (1991) identify three reasons to study policy.First, many of the education policies likely to have a direct effect on the lives of students, parents, and teachers are local school policies. A state legislature may pass legislation concerning the allocation of resources for education, but the legislation does not become meaningful for clients, patrons, and employees until local policy decisions determine how the available resources ill be utilized. Second, schools serving similar groups of students can differ greatly in areas such as student achievement, attendance, dropped rate, teacher morale, and school climate.The third reason to study school policies according to Duke and Canada (1991) is the fact that the number of locally developed policies is likely to increase in the future. Interest in shared decision making, teacher empowerment, school-site management, and the restructuring of schools suggests that the locus of educational policymaking may be shifting. Duke and Canada point out that ample justification exists for he systematic study of local school policy. Such study promises to shed light on school effectiveness, the process of school improvement, and local control of education.In addition, Duke and Canada state as interest in at-risk students grows, questions need to be raised regarding the extent to which local school policies enhance or impede these youngsters chances for success. So frequent and so complicated have problems related to student attendance become that many school systems consider them to be separate from other discipline problems. This fact may be explained, in part, by the relationship teen school attendance and state aid to education and the link between attendance and a students constitutional right to an education.Attendance rul es include those pertaining to unexcused absence from school and class, tardiness, and leaving school without permission. Since, by law, students must attend school up to the state-mandated school-leaving age, attendance- related issues for local policymakers do not concern rules so much as the consequences for absenteeism and attendance practices (Duke and Canada, 1991). In recent years, school policymakers concerned about the relationship teen the time spent in school and student learning have begun to condone denying course credit and awarding failing grades for chronic absenteeism.The number of absences resulting in denial of credit or a failing grade usually ranges from 10 to 24 in a semester (Seeded et al, 1986). According to Eastward (1989), the truant is likely to be a boy and to be in the eleventh or twelfth grade. The student is truant more often as the year progresses, and skip some classes more often than others. He says he skips because he dislikes the classes or considers them to be too boring to attend. However, he does not necessarily intend to drop out of school. This student may have a job, or may have been asked by parents to work at home or care for children.Rood (1989) views absenteeism as a constant interruption of the learning process. The more absences a student accumulates, the less he or she can be expected to adequately participate in and understand classroom activities. Rood continues by stating that it is no secret that the skill levels of many high school students have declined while absenteeism contain uses to increase. He writes that on an average Monday, many urban high schools have an absence rate of more than 30 percent. It is common for many secondary students to miss 20 to 90 days of school in an academic year.Rood (1989), Elevate (1975), and Higher (1987) have identified the following characteristics of non-attendees: Age absenteeism increases as a student progresses through high school. Gender in the first three years of high school, girls will have higher rates of absenteeism than boys will. Race minority students are more likely to be absent than whites. School success students with higher grades and/or IIS have better attendance. Program students in college preparatory programs are present ore often than those in vocational, general, or business programs.Family setting students from a one-parent family have poorer attendance rates than those from the more traditional family. School involvement participants in a variety of co-curricular activities will generally be in attendance more often than will non-participants. Eastward (1989) indicates that some researchers believe that truancy problems can be blamed on ineffective school attendance policies. In some cases the costs in time and energy to enforce compulsory education statutes seem to outweigh the benefits.As a result schools will develop policies that devote the most energy to those students expected to have the best chance of success. Eastward (1989) indicates that the burden of reducing truancy rates rests primarily with schools, and a message that can be drawn from the research is that schools can affect truancy rate whenever they give high priority to effective attendance policies. Eastward identified the most effective policies as those that have the following elements: and outcomes are clear and well publicized Policies are Expectations followed consistently by everyone Students are held responsible for their actions.

Margaret Mead Was A Great Scientist, Explorer, Writer, And Teacher, Wh

Margaret Mead was a great scientist, explorer, writer, and teacher, who educated the human race in many different ways. In the next few paragraphs I will discuss the different ways Margaret Mead, Anthropologist, effected our society. Margaret Mead was born in Philadelphia on December 16, 1901, and was educated at Barnard College and at Columbia University. In 1926 she became assistant curator of ethnology at the American Museum of Natural History in New York City, and she served as associate curator and as curator. She was director of research in contemporary cultures at Columbia University from 1948 to 1950 and professor of anthropology there after 1954. Participating in several field expeditions, Mead conducted notable research in New Guinea, Samoa, and Bali. Much of her work was devoted to a study of patterns of child rearing in various cultures. She also analyzed many problems in contemporary American society, particularly those affecting young people. Her interests were varied, including childcare, adolescence, sexual behavior, and American character and culture. Margaret Mead taught generations of Americans about looking carefully and openly at other cultures to understand the complexities of being human. Margaret Mead brought the serious work of anthropology to public consciousness. Mead studied at Barnard College, where she met the great anthropologist Franz Boas. Franz Boas became her mentor and her advisor when she attended graduate school at Columbia University. Mead's work is largely responsible for the treasures on view in the Museum's Hall of Pacific Peoples. In addition to her work at the Museum, Margaret Mead taught, and wrote more best selling books. She contributed a regular column to Redbook magazine. She was also lectured, and was frequently interviewed on radio and television. A deeply committed activist, Mead often testified on social issues before the United States Congress and other Government agencies. Mead died in New York City on Nove mber 15, 1978. Mead Margaret was an American anthropologist, widely known for her studies of primitive societies and her contributions to social anthropology. She will be remembered everywhere by anthropologist all over the world.