Elżbieta Pleszczyńska (born 20 March 1933) is a Polish full

professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin as a "person who pr ...

statistics Statistics (from German language, German: ''wikt:Statistik#German, Statistik'', "description of a State (polity), state, a country") is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of ...

, activist of

disability rights movement The disability rights movement is a global new social movements, social movement that seeks to secure equal opportunity, equal opportunities and equality before the law, equal rights for all people with disability, disabilities. It is made u ...

Biography

She gained an M.Sc. in mathematics at

University of Warsaw The University of Warsaw ( pl, Uniwersytet Warszawski, la, Universitas Varsoviensis) is a public university in Warsaw, Poland. Established in 1816, it is the largest institution of higher learning in the country offering 37 different fields of ...

, Faculty of Mathematics, Physics and Chemistry in 1956. She held position at Institute of Mathematics PAS until 1972. She received her Ph.D. in 1965 in the area of

discriminant analysis Linear discriminant analysis (LDA), normal discriminant analysis (NDA), or discriminant function analysis is a generalization of Fisher's linear discriminant, a method used in statistics and other fields, to find a linear combination of features ...

("Power of Test, and Separability of Hypothesis in Statistical Design of Experiments"). Her

habilitation Habilitation is the highest university degree, or the procedure by which it is achieved, in many European countries. The candidate fulfills a university's set criteria of excellence in research, teaching and further education, usually including a ...

thesis, titled "Trend Estimation Problems in Time Series Analysis", was accepted in 1973. In 1967/8 she was visiting researcher in University of Wales (Great Britain), and in 1971/2 in University of Montreal. In 1973 she moved to the Institute of Computer Science, PAS. In 1977, 1979 and 1989 she was awarded by the Polish Academy of Science. In 1981 she visited

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

invited by CNR. In the 1990s she started (together with her team) so called grade data analysis, a science of applying copula and rank methods to problems of correspondence and

cluster analysis Cluster analysis or clustering is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense) to each other than to those in other groups (clusters). It is a main task of ...

together with

outlier In statistics, an outlier is a data point that differs significantly from other observations. An outlier may be due to a variability in the measurement, an indication of novel data, or it may be the result of experimental error; the latter are ...

detection. (The adjective ''grade'' here honors statisticians of the first half of the 20th century, who called

cumulative distribution function In probability theory and statistics, the cumulative distribution function (CDF) of a real-valued random variable X, or just distribution function of X, evaluated at x, is the probability that X will take a value less than or equal to x. Ev ...

s in this way.) In 1993 the

President of the Republic of Poland The president of Poland ( pl, Prezydent RP), officially the president of the Republic of Poland ( pl, Prezydent Rzeczypospolitej Polskiej), is the head of state of Poland. Their rights and obligations are determined in the Constitution of Polan ...

awarded Elżbieta Pleszczyńska with the Full Professor title in the area of mathematics. In 2000 she was an invited consultant of the

Cambridge University , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...

. In the Institute of Computer Science PAS, she had been leader of the Statistical Data Analysis division for many years. According to the Polish law, professors in PAS must retire at the age of 70. Retirement in 2003, although a bit confusing, didn't stop her scientific and social activity.

Scientific views

Prof. Pleszczyńska is known for her criticism of the classic statistical approach. Classic parametric methods, like Pearson correlation coefficient, or

least squares method The method of least squares is a standard approach in regression analysis to approximate the solution of overdetermined systems (sets of equations in which there are more equations than unknowns) by minimizing the sum of the squares of the res ...

produce comparable results only for comparable distribution types (in practice multivariate normal distribution is being assumed). Parametric statistical tests are derived from distribution assumptions. Classic methods fail if the input data contain strong outliers, and interpretation of their results should be different for different distribution types. In practice, the underlying assumptions are often not checked, moreover they are always violated – there is no normal distribution in the real world, because every real variable is limited (for example people cannot be –170 cm or +2 km tall), and the normal distribution implies positive probability density for every

real number In mathematics, a real number is a number that can be used to measure a ''continuous'' one-dimensional quantity such as a distance, duration or temperature. Here, ''continuous'' means that values can have arbitrarily small variations. Every real ...

. In most cases the real distribution is

skewed In probability theory and statistics, skewness is a measure of the asymmetry of the probability distribution of a real-valued random variable about its mean. The skewness value can be positive, zero, negative, or undefined. For a unimoda ...

discrete Discrete may refer to: *Discrete particle or quantum in physics, for example in quantum theory * Discrete device, an electronic component with just one circuit element, either passive or active, other than an integrated circuit *Discrete group, a ...

, which does not prevent people from using normal distribution methods. The extent of this violation can be measured, but its maximum accepted level is just a convention, not mathematics. The parametric methods always work out of their conditions of use. However, their results are often considered valid, which leads to "scientific" validation of false hypothesis. For the reasons mentioned above, Elżbieta Pleszczyńska is a strong advocate of

explorative data analysis In statistics, exploratory data analysis (EDA) is an approach of analyzing data sets to summarize their main characteristics, often using statistical graphics and other data visualization methods. A statistical model can be used or not, but prim ...

and

non-parametric statistics Nonparametric statistics is the branch of statistics that is not based solely on parametrized families of probability distributions (common examples of parameters are the mean and variance). Nonparametric statistics is based on either being distr ...

, like Spearman's rho,

Kendall's tau In statistics, the Kendall rank correlation coefficient, commonly referred to as Kendall's τ coefficient (after the Greek letter τ, tau), is a statistic used to measure the ordinal association between two measured quantities. A τ test is a non ...

, or grade data analysis.

Selected works

* * * *

Social work

Elżbieta Pleszczyńska has cofounded Foundation Supporting Physically Disabled Mathematicians and Computer Specialists in

Warsaw Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officia ...

(September 1990). For many years she has been the Foundation chairman. The Foundation under her leadership was mainly interested in the professional advancement of physically disabled people via technology and

remote work Remote work, also called work from home (WFH), work from anywhere, telework, remote job, mobile work, and distance work is an employment arrangement in which employees do not commute to a central place of work, such as an office building, ware ...

. Pleszczyńska has been continuously focusing attention of the public opinion on rights of disable people, in her periodical reports.

Private life

She had a son, , journalist, and has two grandchildren. She lived in Warsaw Wola district. Since July, 2019, in elderly care.

References

External links

* * {{DEFAULTSORT:Pleszczynska, Elzbieta Polish disability rights activists Polish statisticians Women statisticians Living people 1933 births Scientists from Warsaw