Sri Lanka Scientific Service Exam key terms

A structured way of gaining knowledge in which observations lead to testable hypotheses, predictions are checked against evidence, and conclusions are revised when new data conflict with them.

A clear, testable statement proposing a relationship between variables, framed so that data collected in a study could support or contradict it.

The default statistical statement that no real effect or difference exists; researchers test whether observed data are unlikely enough under this assumption to reject it.

The property of a scientific claim being stated precisely enough that some conceivable observation could show it to be wrong, which distinguishes testable science from unfalsifiable assertion.

A precise description of how a variable is measured or manipulated in a study, such as defining growth as increase in shoot length in millimetres over 14 days.

The factor that a researcher deliberately changes or selects in an experiment, so that its effect on the measured outcome can be observed.

The outcome that is measured in an experiment and expected to change in response to manipulation of the independent variable.

Any condition held constant across treatment groups so that it cannot explain differences in the outcome, such as temperature, light period, or reagent batch.

An unmeasured factor that is linked both to the supposed cause and to the outcome, creating a spurious association that can mislead interpretation.

Assignment of subjects or samples to groups by chance, which reduces systematic bias and makes groups comparable on average before treatment begins.

A comparison group that does not receive the treatment under test, or receives a placebo, providing a baseline against which the treated group is judged.

A study design in which participants, assessors, or both do not know which treatment was given, reducing expectation effects and measurement bias.

Repetition of a study or measurement, by the same or other researchers, to check whether findings are consistent rather than chance results of one experiment.

The consistency of a measurement or instrument, meaning repeated measurements under the same conditions give closely similar results.

The extent to which a method or instrument actually measures the concept it claims to measure, rather than something related but different.

The degree to which a study's design allows a causal conclusion, free from confounding, selection bias, and measurement error.

A distortion that arises when the sample studied is not representative of the target population, so results do not generalise as claimed.

The number of observations or subjects included in a study, which strongly affects the precision of estimates and the ability to detect real effects.

The probability that a study will detect a real effect of a given size, increasing with sample size, lower variability, and larger true effect.

Rejecting a true null hypothesis, that is, reporting an effect that does not really exist; its long-run rate is controlled by the significance level chosen.

Failing to reject a false null hypothesis, meaning a real effect was missed; its probability falls as statistical power rises.

The probability of obtaining data at least as extreme as those observed if the null hypothesis were true; it is not the probability that the hypothesis is true.

A decision that observed results are unlikely under the null hypothesis at a pre-set threshold, commonly 0.05, indicating an effect worth further attention rather than proof.

A range of values, calculated from sample data, that is expected to contain the true population parameter with a stated probability such as 95 percent.

A measure of how widely individual values spread around the mean of a dataset, expressed in the same units as the data.

The standard deviation of a statistic's sampling distribution, showing how much an estimate such as a mean would vary between repeated samples.

A symmetric bell-shaped probability distribution defined by its mean and standard deviation, in which most values cluster near the centre and extremes are rare.

Summary measures that describe a dataset without inferring beyond it, including means, medians, ranges, and standard deviations.

Methods that use sample data to draw conclusions about a wider population, including estimation, confidence intervals, and hypothesis tests.

Independent assessment of a manuscript by specialists in the field before publication, intended to check soundness, originality, and clarity of the work.

Presenting another person's words, data, or ideas as one's own without adequate attribution, a serious breach of research and publication ethics.

Principles governing responsible conduct of research, covering honesty in reporting, fair treatment of participants, consent, confidentiality, and avoidance of harm.

Voluntary agreement by a research participant after being told the purpose, procedures, risks, and rights involved, given without coercion and documented appropriately.

A situation where financial or personal interests could improperly influence professional judgement, requiring disclosure and sometimes management or withdrawal.

A written plan setting out background, objectives, methods, timeline, budget, and expected outcomes, used to obtain approval and funding before a study begins.

A critical survey of existing published work on a topic, used to establish what is known, identify gaps, and justify a new study's questions and methods.

A formal request for research funding that states objectives, methodology, budget justification, and expected impact, assessed competitively by the funding body.

The regulated process by which state bodies obtain goods, works, and services, typically requiring transparent bidding, evaluation against published criteria, and documented award decisions.

The structured scoring of bids against pre-announced technical and financial criteria by a committee, recorded so that the award decision can be audited.

A periodic, documented assessment of an employee's work against agreed objectives and competencies, used for development and administrative decisions.

The internationally agreed system of measurement units, with seven base units including metre, kilogram, second, ampere, kelvin, mole, and candela.

The digits in a reported number that carry meaningful information about measurement precision, governing how a calculated result should be rounded.

A quantified range describing how far a measured value may lie from the true value, arising from instrument limits, technique, and random variation.

Checking or deriving equations by comparing the base units on each side, since physically valid equations must have matching dimensions.

A logarithmic scale from 0 to 14 expressing hydrogen ion activity in a solution, where values below 7 are acidic and above 7 are basic.

Concentration expressed as moles of solute per litre of solution, the standard way of stating reagent strength in laboratory work.

A solution that resists large changes in pH when small amounts of acid or base are added, usually made from a weak acid and its conjugate base.

A plot of instrument response against known standard concentrations, used to convert the signal from an unknown sample into a concentration.

An analytical technique that measures how much light a sample absorbs at a chosen wavelength, allowing concentration to be estimated via Beer-Lambert behaviour.

A set of practices that keep cultures and work surfaces free of contaminating microorganisms, including sterilising tools, flaming necks, and working near a flame or hood.

The destruction or removal of all viable microorganisms from equipment or media, commonly by autoclaving, dry heat, filtration, or radiation.

Planned checks on processes and outputs, such as standards, blanks, and duplicates, that confirm results meet defined accuracy and precision criteria.

The variety of living organisms at genetic, species, and ecosystem levels, often assessed through species richness and abundance in defined survey areas.

The benefits people obtain from functioning ecosystems, such as clean water, pollination, flood control, and soil formation, often valued in policy decisions.

A formal process that predicts the likely environmental effects of a proposed project and sets mitigation and monitoring conditions before approval is granted.

Systematic identification of hazards, estimation of the likelihood and severity of harm, and specification of controls to reduce risk to an acceptable level.

The movement of knowledge, methods, or equipment from a research setting to industry or public services so that findings become practical applications.

Government decisions on funding, priorities, regulation, and institutions for research and innovation, shaping how scientific capacity is built and used nationally.