In statistics, the standard score is the signed fractional number of standard deviations by which the value of an observation or data point is above or below the mean value of what is being observed or measured. Observed values above the mean have positive standard scores, while values below the mean have negative standard scores, it is calculated by subtracting the population mean from an individual raw score and dividing the difference by the population standard deviation. It is a dimensionless quantity; this conversion process is called normalizing. Standard scores are called z-values, z-scores, normal scores, standardized variables, they are most used to compare an observation to a theoretical deviate, such as a standard normal deviate. Computing a z-score requires knowing the mean and standard deviation of the complete population to which a data point belongs. If the population mean and population standard deviation are known, the standard score of a raw score x is calculated as z = x − μ σ where: μ is the mean of the population.
Σ is the standard deviation of the population. The absolute value of z represents the distance between the raw score and the population mean in units of the standard deviation. Z is negative. Calculating z using this formula requires the population mean and the population standard deviation, not the sample mean or sample deviation, but knowing the true mean and standard deviation of a population is unrealistic except in cases such as standardized testing, where the entire population is measured. When the population mean and the population standard deviation are unknown, the standard score may be calculated using the sample mean and sample standard deviation as estimates of the population values. In these cases, the z score is z = x − x ¯ S where: x ¯ is the mean of the sample. S is the standard deviation of the sample; the z-score is used in the z-test in standardized testing – the analog of the Student's t-test for a population whose parameters are known, rather than estimated. As it is unusual to know the entire population, the t-test is much more used.
The standard score can be used in the calculation of prediction intervals. A prediction interval, consisting of a lower endpoint designated L and an upper endpoint designated U, is an interval such that a future observation X will lie in the interval with high probability γ, i.e. P = γ, For the standard score Z of X it gives: P = γ. By determining the quantile z such that P = γ it follows: L = μ − z σ, U = μ + z σ In process control applications, the Z value provides an assessment of how off-target a process is operating; when scores are measured on different scales, they may be converted to z-scores to aid comparison. Dietz et al. give the following example comparing student scores on the SAT and ACT high school tests. The table shows the mean and standard deviation for total score on the SAT and ACT. Suppose that student A scored 1800 on the SAT, student B scored 24 on the ACT. Which student performed better relative to other test-takers? The z-score for student A is z = x − μ σ = 1800 − 1500 300 = 1 The z-score for student B is z = x − μ σ = 24 − 21 5 = 0.6 Because student A has a higher z-score than student B, student A performed better compared to other test-takers than did student B.
Continuing the example of ACT and SAT scores, if it can be further assumed that both ACT and SAT scores are distributed the z-scores may be used to calculate the percentage of test-takers who received lower scores than students A and B. "For some multivariate techniques such as multidimensional scaling and cluster analysis, the concept of distance between the units in the data is of considerable interest and importance … When the variables in a multivariate data set are on different scales, it makes more sense to calculate the distances after some form of standardization." In principa
Franciscan Sisters of Baltimore were the American members of a Roman Catholic religious congregation of women founded in the London suburb of Mill Hill, England, in 1868. Connected to the Society of Mill Hill Missionaries from the time of their founding, they were committed to serving the needy of the world. Members of the congregation came to the United States in 1881, where they were the first white religious order dedicated to serve the African-American population of Baltimore; the United States Province merged with an American congregation of Franciscan Sisters in 2001. In 1866, the future English cardinal, Herbert Vaughan felt that the newly emancipated Catholic Church of Great Britain needed to establish its presence in the new nations of the British Empire, so as not to concede their populations to the missionary work of the Anglican and Protestant Churches. To this end, he founded the Missionary Society of St. Joseph, better known as the Mill Hill Missionaries, to be a society of Catholic priests dedicated to the foreign missions.
Out of this vision, he approached the new Archbishop of Westminster, Cardinal Wiseman, to request his approval for a missionary college to educate Catholic clergy to serve overseas. Wiseman agreed to this proposal and Vaughan established St. Joseph's Missionary College at Holcombe House in Mill Hill. In 1868 Vaughan received a group of Anglican Franciscan Sisters living in Hammersmith into the Roman Catholic Church. Under the leadership of Mother Mary Francis of the Five Wounds, they were thereby founded as the Franciscan Sisters of the Five Wounds; when the missionary college moved to larger quarters in 1871, Vaughan offered the use of the house to the Sisters, which they accepted. Unknown to them, Vaughan's goal had been to find religious sisters to staff the domestic department of the college; this the Sisters refused to do. They joined in the work of the Society in the United States and Uganda; the following year Vaughan received an appeal from the American Catholic bishops, resulting from their deliberations at the Tenth Provincial Council of Baltimore held in 1869.
The American bishops saw the deplorable conditions of many of the African-Americans newly freed from slavery by the American Civil War without any means of sustaining themselves. The fifth decree of the Council called upon the bishops of the nation to provide missions and schools for all black Americans in their dioceses, as education was seen as a critical need by that population. Vaughan had been petitioning the Holy See for assignment to some region where his missionaries could serve, mentioned this request in his communications. In 1871, Pope Pius IX granted both requests, assigning the society to serve the African-American residents of the Archdiocese of Baltimore as Apostolic Missionaries, subject directly to Rome. In 1881, five Franciscan Sisters of the Five Wounds came to the United States at the invitation of Cardinal James Gibbons, the Archbishop of Baltimore, to care for the many homeless African American children wandering the streets of that city. Working with the Mill Hill Fathers, an orphanage was opened at the intersections of Maryland Avenue and 23rd Street which the Sisters operated until 1950.
As American girls began to enter the congregation, the Sisters became engaged in teaching. They taught in several schools of the city, in Catholic schools in the Archdiocese of New York and the Diocese of Richmond. After the closing of the orphanage, the Sisters opened there the St. Francis School for Special Education in 1953, in order to meet the needs of that group of children; as a result of requests by the community for help with these children as they passed school age, in 1961 they opened the St. Elizabeth School for Special Education, dedicated with a 160 student enrollment capacity. During the mid-1960s, as the Franciscan Sisters saw the growing tensions of the American inner city populations and the riots in their own neighborhoods, they looked for other ways to meet the needs of those around them. In answer to a need expressed by the local community, in 1968 they opened the Franciscan Center of Baltimore to provide emergency food and clothing, it was opened under the supervision of Sister Irene Marshiano, O.
S. F. and continues to operate. In 1993 the Franciscan Sisters celebrated the 125th anniversary of the founding of the congregation, their celebration was marred, however, by the recent murder of the superior of the convent which housed their retired members, Sister MaryAnn Glinka, O. S. F. in a crime which shocked and terrified the people of the city. By the end of the 20th century, the Sisters were faced with both an aging membership and few new applicants, they made the decision to merge with the Sisters of St. Francis of Assisi based in St. Francis, Wisconsin; the merger took place on October 4, 2001, the feast day of St. Francis of Assisi
PS Decoy is a owned paddle steamer, believed to be the only sea-going paddle steamer in the Southern Hemisphere. Built in 1986 in Fremantle, Decoy is a replica of the original paddle steamer that operated on the Swan River in the 1870s, she was used in the filming of the television mini-series Cloudstreet, based on Tim Winton's novel. Decoy was built by Australian Ship Building Industries in Fremantle in 1986, a replica of the original paddle steamer that operated on the Swan River in the 1870s. Chas Cox upgraded the vessel. Decoy is powered by a 1905 Ransome Sims and Jefferies twin cylinder steam engine, salvaged and restored from Bunnings engineering workshops in Manjimup; the engine was rebuilt in 1986 with a new oil fired burner and maxitherm boiler fitted. As of 2011 Decoy is used for weddings and corporate events, operating on the Swan River. PS Decoy Official Website PS Decoy Official Facebook Page