Lack-of-fit sum of squares 1970-01-01
Lack-of-fit sum of squares is a measure used in statistical modeling and regression analysis to assess how well a model fits a given set of data. Specifically, it helps to identify whether the model is providing a good description of the underlying relationship between the independent and dependent variables.
Lady tasting tea 1970-01-01
The "Lady tasting tea" is a famous thought experiment introduced by the statistician Ronald A. Fisher in his 1935 book "The Design of Experiments." The scenario serves as an illustration of hypothesis testing and the logic of statistical inference. In the thought experiment, a lady claims she has the ability to distinguish between tea that has been brewed with milk added first and tea that has the milk added after brewing.
Latin hypercube sampling 1970-01-01
Latin hypercube sampling (LHS) is a statistical method used to generate a sample of plausible combinations of parameters from a multidimensional distribution. It is particularly useful in the context of uncertainty analysis and simulation studies where one needs to efficiently sample from multiple input variables. ### Key Characteristics of Latin Hypercube Sampling: 1. **Stratified Sampling**: LHS divides each dimension (input variable) into equally sized intervals (strata) and ensures that each interval is sampled exactly once.
Latin rectangle 1970-01-01
A Latin rectangle is a mathematical concept that extends the idea of a Latin square. Specifically, a Latin rectangle is an \( m \times n \) arrangement of \( m \) different symbols (or elements), where \( m \leq n \), such that each symbol appears exactly once in each row and at most once in each column. To break this down further: - **Rows**: The rectangle has \( m \) rows.
Pool testing, also known as group testing, is a strategy used to efficiently test multiple individuals for COVID-19. The approach involves combining samples from several people and testing them as a group. If the pool tests negative, everyone in that group is presumed negative. If the pool tests positive, individual samples from that group are then tested to identify who is positive. Many countries have implemented pool testing strategies at various points during the COVID-19 pandemic.
Longitudinal study 1970-01-01
A longitudinal study is a research design that involves repeated observations of the same variables (such as individuals, groups, or phenomena) over an extended period of time, which can range from months to many years or even decades. Longitudinal studies are often used in various fields, including psychology, sociology, medicine, and education, to track changes and developments, identify trends, and examine causal relationships.
Manipulation check 1970-01-01
A manipulation check is a procedure used in experimental research to determine whether the manipulation of an independent variable has had the intended effect on participants. Essentially, it helps researchers verify that the experiment successfully influenced the participants in the way they intended.
Minimisation (clinical trials) 1970-01-01
Minimisation is a randomisation technique used in clinical trials to ensure that treatment groups are comparable with respect to certain baseline characteristics. It is particularly useful in small trials where random assignment alone may result in imbalances between groups. The primary goal of minimisation is to reduce the potential for bias that could affect the trial's outcomes. In a minimisation process, as each participant is assigned to a treatment group, the allocation is influenced by existing group characteristics.
Multifactor design of experiments software 1970-01-01
Multifactor design of experiments (DOE) software is a specialized tool used to analyze the effects of multiple factors on a response variable within experimental setups. It helps researchers and practitioners conduct structured experiments with the aim of identifying the interactions between different variables and optimizing processes. ### Key Features of Multifactor DOE Software: 1. **Factorial Designs:** The software allows users to set up full or fractional factorial designs, enabling them to explore combinations of factors to see how they affect the outcome.
Multiple baseline design 1970-01-01
Multiple baseline design is a type of research design commonly used in behavioral sciences, particularly in the field of psychology and education. It is primarily applied in single-subject research, but it can also be useful in small group settings. The key features of multiple baseline design include: 1. **Staggered Introduction**: The intervention or treatment is introduced at different times across multiple subjects, behaviors, or settings.
Multiple treatments 1970-01-01
The term "multiple treatments" can refer to various contexts depending on the field of study or application. Here are a few interpretations: 1. **Healthcare and Medicine**: In a medical context, multiple treatments refer to the use of more than one therapeutic approach or intervention to manage a patient’s condition. This could involve combining different types of medications, therapies (like physical therapy alongside medication), or medical interventions (like surgery and rehabilitation).
Multivariate analysis of variance 1970-01-01
Multivariate Analysis of Variance (MANOVA) is a statistical technique used to assess whether there are any statistically significant differences between the means of multiple dependent variables across different groups or levels of one or more independent variables. It is essentially an extension of Analysis of Variance (ANOVA), which deals with a single dependent variable.
N of 1 trial 1970-01-01
An N of 1 trial is a type of experimental design used in clinical research, particularly in the fields of medicine and psychology, where a single patient (the "N" refers to the number of participants in the trial) is studied over time to evaluate the effects of a treatment or intervention. In these trials, the individual serves as their own control, allowing researchers to assess the efficacy and safety of a treatment on that specific person.
National Research Ethics Service 1970-01-01
The National Research Ethics Service (NRES) was a part of the UK's National Health Service (NHS) responsible for overseeing the ethical review of research involving human participants. Its primary aim was to ensure that research is conducted ethically, safeguarding the rights, dignity, and welfare of participants. NRES provided a framework for the review of healthcare and biomedical research protocols, ensuring compliance with ethical standards and regulations.
Nested case–control study 1970-01-01
A nested case–control study is a type of observational epidemiological study that is designed to investigate associations between exposures and outcomes within a well-defined cohort. This study design is "nested" within a larger cohort study, which means that it utilizes data collected from participants in that cohort to identify cases and controls.
Null hypothesis 1970-01-01
The null hypothesis is a fundamental concept in statistics and hypothesis testing. It is a statement that asserts there is no effect or no difference in a given situation, and it serves as a default or starting position for statistical analysis. The null hypothesis is usually denoted as \( H_0 \). For example, in a clinical trial, the null hypothesis might state that a new medication has no effect on patients compared to a placebo.
Null result 1970-01-01
A null result refers to an outcome in an experiment or study that shows no significant effect or relationship between variables, essentially indicating that the hypothesis being tested is not supported by the data. This term is often used in scientific research, particularly in fields like physics, psychology, and medicine, where researchers may expect to find a specific outcome.
Nuremberg Code 1970-01-01
The Nuremberg Code is a set of ethical principles for conducting research on human subjects, established in the aftermath of World War II during the Nuremberg Trials. It was developed in response to the inhumane medical experiments conducted by Nazi doctors on concentration camp prisoners. The Code was published in 1947 and has ten key principles, which emphasize the necessity of informed consent, the importance of minimizing risk, and the obligation of researchers to prioritize the welfare of participants.
Observational study 1970-01-01
An observational study is a type of research method used in various fields, including medicine, social sciences, and epidemiology, where researchers observe and collect data on subjects without manipulating any variables or assigning treatments. In an observational study, the researcher does not control the environment or conditions under which the data is collected, and participants are not randomly assigned to different groups. There are several key characteristics of observational studies: 1. **No Intervention**: Researchers simply observe what is occurring naturally without trying to influence outcomes.
Observer-expectancy effect 1970-01-01
The observer-expectancy effect, also known as the experimenter-expectancy effect or Rosenthal effect, refers to a cognitive bias that occurs when a researcher's expectations or beliefs about the outcome of a study subtly influence the behavior of participants, which in turn affects the results of the research.