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Question 1Foundations, Terminology and Scope (provisional)

In statistics, the entire collection of individuals or items about which a study draws conclusions is called the:

  1. population Correct answer.
  2. sample
  3. sampling frame
  4. census

Explanation

The population is the complete set of units a study targets, whether or not every unit is actually observed. A sample is only a subset of that set, used to gain information about the whole.

Question 2Foundations, Terminology and Scope (provisional)

A numerical measure that describes a characteristic of an entire population is called a:

  1. parameter Correct answer.
  2. sample
  3. variable
  4. statistic

Explanation

Parameters describe populations and are usually unknown, while statistics describe samples and are computed from collected data. Inferential methods use sample statistics to estimate population parameters.

Question 3Foundations, Terminology and Scope (provisional)

A researcher calculates the average age of the 200 people surveyed and reports it in a summary table. This activity is an example of:

  1. probability theory
  2. sampling design
  3. inferential statistics
  4. descriptive statistics Correct answer.

Explanation

Descriptive statistics summarize or display the data actually collected, without generalizing beyond them. Inferential statistics would instead use the sample to draw conclusions about a larger population.

Question 4Foundations, Terminology and Scope (provisional)

An HR system records each employee's department as 'Sales', 'Finance' or 'Operations'. This variable is measured on which scale?

  1. ordinal
  2. nominal Correct answer.
  3. ratio
  4. interval

Explanation

Nominal scales use labels that merely name or classify categories, with no meaningful order. Departments cannot be ranked, and arithmetic on the labels is meaningless.

Question 5Foundations, Terminology and Scope (provisional)

The number of defective parts found in each batch of 100 is best classified as a:

  1. continuous quantitative variable
  2. discrete quantitative variable Correct answer.
  3. nominal categorical variable
  4. ordinal categorical variable

Explanation

A count takes only whole-number values, which makes it discrete quantitative. Continuous variables, by contrast, can take any value within an interval, such as a measured length.

Question 6Foundations, Terminology and Scope (provisional)

A study that obtains data from every member of the population is called a:

  1. sample survey
  2. census Correct answer.
  3. pilot study
  4. case study

Explanation

A census measures every unit of the population, so it is not subject to sampling error, although other errors can still occur. A sample survey observes only part of the population.

Question 7Foundations, Terminology and Scope (provisional)

Which of the following is a qualitative (categorical) variable?

  1. marital status Correct answer.
  2. height in centimeters
  3. annual income
  4. number of employees

Explanation

Qualitative variables record group membership or labels rather than amounts. Marital status places a person into a category, so it is categorical.

Question 8Foundations, Terminology and Scope (provisional)

Compared with an experiment, an observational study is characterized by the fact that the researcher:

  1. manipulates the explanatory variable
  2. does not assign treatments Correct answer.
  3. controls the placebo effect
  4. assigns treatments at random

Explanation

In an observational study the researcher records what occurs without imposing a treatment, so causal conclusions are weaker. Experiments, by contrast, actively assign treatments to units.

Question 9Foundations, Terminology and Scope (provisional)

Temperature measured in degrees Celsius is an example of which level of measurement?

  1. ordinal
  2. interval Correct answer.
  3. ratio
  4. nominal

Explanation

Celsius has equal intervals between degrees but an arbitrary zero, so differences are meaningful while ratios are not. A 20 degree day is not twice as warm as a 10 degree day on this scale.

Question 10Foundations, Terminology and Scope (provisional)

Which of these variables is measured on a ratio scale?

  1. year of birth
  2. customer satisfaction on a 1-5 rating
  3. grade of service: poor, fair, good
  4. time to complete a task Correct answer.

Explanation

Ratio scales have a true zero, so differences and ratios are both meaningful; a task taking 20 minutes takes twice as long as one taking 10. Ratings, calendar years and ordered grades lack a true zero.

Question 11Foundations, Terminology and Scope (provisional)

A list of all the units in the target population from which a sample is actually drawn is called the:

  1. sampling frame Correct answer.
  2. sampling distribution
  3. target population
  4. sample space

Explanation

The sampling frame is the practical list or register used to select units. If it omits some population members, coverage error results.

Question 12Foundations, Terminology and Scope (provisional)

A radio station invites listeners to call in and vote on a policy question. The main weakness of this approach is:

  1. self-selection bias Correct answer.
  2. measurement error in the scale
  3. excessive random assignment
  4. too small a target population

Explanation

Only listeners with strong opinions and the means to call take part, so respondents effectively choose themselves. The resulting group is not representative of the population of interest.

Question 13Foundations, Terminology and Scope (provisional)

Data gathered directly by the researcher for the purpose of the current study are called:

  1. secondary data
  2. administrative data
  3. primary data Correct answer.
  4. tertiary data

Explanation

Primary data are collected first-hand for the specific question at hand, for example through a newly designed survey. Secondary data were collected earlier, often for a different purpose.

Question 14Foundations, Terminology and Scope (provisional)

Quarterly unemployment rates for a country from 2010 to 2023 form a:

  1. stratified sample
  2. cross-sectional data set
  3. nominal data set
  4. time series Correct answer.

Explanation

A time series records one or more variables at successive points in time, so the order of the observations carries information. Cross-sectional data describe many units at a single point in time.

Question 15Foundations, Terminology and Scope (provisional)

In standard statistical notation, the mean of a sample of size n is written as:

  1. sigma
  2. x-bar Correct answer.
  3. s
  4. mu

Explanation

Roman letters denote sample quantities, so x-bar is the sample mean and s the sample standard deviation. Greek letters such as mu and sigma denote the corresponding population values.

Question 16Foundations, Terminology and Scope (provisional)

A study reports that students who eat breakfast score higher on exams, but breakfast eaters also tend to sleep longer. In this context, sleep is best described as a:

  1. confounding variable Correct answer.
  2. dependent variable
  3. sampling error
  4. control variable

Explanation

A confounding variable is associated with both the explanatory variable and the outcome, so its effect cannot be separated from the effect of interest. Because sleep differs between the groups, the breakfast comparison is muddled.

Question 17Foundations, Terminology and Scope (provisional)

Guests rate a hotel's service as 'poor', 'fair', 'good' or 'excellent'. These responses are measured on which scale?

  1. interval
  2. ratio
  3. ordinal Correct answer.
  4. nominal

Explanation

The categories form a meaningful order, but the distances between them are not defined numerically. That combination of ordered categories without equal spacing defines an ordinal scale.

Question 18Foundations, Terminology and Scope (provisional)

The main purpose of random sampling is to:

  1. guarantee the sample mean equals the population mean
  2. increase the sample size
  3. remove all measurement error
  4. reduce selection bias Correct answer.

Explanation

Random selection gives every unit a known chance of inclusion, which avoids systematic favouritism in choosing the sample. It does not eliminate random sampling error, whose size is governed mainly by sample size.

Question 19Foundations, Terminology and Scope (provisional)

Using data from a sample to estimate an unknown population mean is an example of:

  1. graphical display
  2. descriptive statistics
  3. data editing
  4. inferential statistics Correct answer.

Explanation

Inferential statistics generalize from a sample to a population, often attaching a margin of error to the estimate. Descriptive statistics stop at summarizing the observed data themselves.

Question 20Foundations, Terminology and Scope (provisional)

Which of the following variables is continuous?

  1. number of defects per lot
  2. number of goals scored in a match
  3. weight of a package Correct answer.
  4. number of cars in a parking lot

Explanation

A continuous variable can take any value within an interval, so it arises from measurement rather than counting. Weight can be recorded to whatever precision the weighing instrument allows.

Question 21Foundations, Terminology and Scope (provisional)

A firm surveys 500 of its 20,000 employees and finds that 62% are satisfied. In this setting the 62% is a _____, while the satisfaction rate of all 20,000 employees would be a _____.

  1. parameter; statistic
  2. statistic; statistic
  3. statistic; parameter Correct answer.
  4. parameter; parameter

Explanation

Values computed from a sample are statistics, while values describing the whole population are parameters. The survey figure comes from 500 employees, so it is a statistic used to estimate the unknown population parameter.

Question 22Foundations, Terminology and Scope (provisional)

Which statement correctly describes an interval scale?

  1. It has a true zero, so ratios can be interpreted
  2. It permits only classification into categories
  3. It merely ranks categories from low to high
  4. Differences are meaningful, but ratios are not Correct answer.

Explanation

An interval scale has equal distances between successive values but an arbitrary zero point, so subtraction is meaningful while division is not. Calendar years and Celsius temperature are standard examples.

Question 23Foundations, Terminology and Scope (provisional)

A researcher draws a sample from a list that contains only landline telephone numbers. The most likely source of bias is:

  1. interviewer bias
  2. nonresponse bias
  3. undercoverage Correct answer.
  4. recall bias

Explanation

Undercoverage occurs when the sampling frame leaves out part of the target population, here households with no landline. Such households can never be selected, no matter how large the sample becomes.

Question 24Foundations, Terminology and Scope (provisional)

A five-point Likert item is often treated as ordinal because:

  1. the categories are unordered labels
  2. differences between points are always equal
  3. gaps between categories may not be equal Correct answer.
  4. it has a true zero point

Explanation

Respondents indicate a position along an ordered scale, but there is no guarantee that the distance between adjacent response points is constant. Treating the item as interval-level requires that equal-spacing assumption to be justified.

Question 25Foundations, Terminology and Scope (provisional)

A mail survey is sent to 1,000 randomly chosen alumni; only 25% respond, and non-respondents tend to have lower incomes. The main threat to the validity of the results is:

  1. measurement error
  2. nonresponse bias Correct answer.
  3. sampling error
  4. coverage error

Explanation

When people who do not respond differ systematically from those who do, estimates based on respondents are biased. Random selection controlled coverage and sampling variation, but it cannot correct selective nonresponse.

Question 26Foundations, Terminology and Scope (provisional)

A coach calculates the mean height of the 20 players on a team and reports the value, without using it to draw any conclusion about players outside the team. This activity is best described as:

  1. parameter estimation
  2. probability sampling
  3. inferential statistics
  4. descriptive statistics Correct answer.

Explanation

Descriptive statistics summarize or describe the data actually observed, with no attempt to generalize beyond that group. Inference begins only when sample results are used to draw conclusions about a larger population.

Question 27Foundations, Terminology and Scope (provisional)

A researcher divides a city's households into income brackets and then takes a random sample of households from within each bracket. This sampling method is:

  1. simple random sampling
  2. systematic sampling
  3. cluster sampling
  4. stratified sampling Correct answer.

Explanation

Stratified sampling splits the population into subgroups (strata) that are internally more alike, then draws a random sample from every stratum. Cluster sampling instead selects entire existing groups and studies all or part of each selected group.

Question 28Foundations, Terminology and Scope (provisional)

Football players wear shirt numbers ranging from 1 to 99. For statistical purposes, these shirt numbers are measured on which scale?

  1. ordinal
  2. ratio
  3. interval
  4. nominal Correct answer.

Explanation

Shirt numbers are labels that identify players; the digits carry no order and no arithmetic meaning, so they are nominal. A variable is not quantitative merely because its values are written as numerals.

Question 29Foundations, Terminology and Scope (provisional)

In a trial of a new drug, neither the participants nor the clinicians who assess the outcomes know which participants received the drug and which received the placebo. This design feature is called:

  1. single blinding
  2. double blinding Correct answer.
  3. randomization
  4. blocking

Explanation

Double blinding means two parties - typically participants and outcome assessors - are kept unaware of treatment assignment. This guards against placebo effects reported by participants and conscious or unconscious bias in those judging outcomes.

Question 30Foundations, Terminology and Scope (provisional)

A sample survey gives an estimate that differs from the true population value solely because only part of the population was observed. This discrepancy is called:

  1. nonresponse bias
  2. sampling error Correct answer.
  3. response error
  4. coverage error

Explanation

Sampling error is the natural variation between a sample estimate and the population value that arises from observing a subset rather than the whole population. The other terms describe mistakes or distortions in how the data were obtained, not the inherent variability of sampling.

Question 31Core Principles and Frameworks (provisional)

Which statement best defines a scientific hypothesis?

  1. A description of a single observed event
  2. A widely accepted explanation supported by evidence
  3. A personal opinion that cannot be measured
  4. A testable prediction derived from prior knowledge Correct answer.

Explanation

A hypothesis is a proposed, testable explanation or prediction that can be evaluated with observations or experiments. It is narrower than a theory and must be falsifiable.

Question 32Core Principles and Frameworks (provisional)

Which principle is part of classical cell theory?

  1. Cells arise spontaneously from nonliving material
  2. All living organisms are composed of cells Correct answer.
  3. Only multicellular organisms contain DNA
  4. Cell membranes are made of cellulose

Explanation

Classical cell theory states that all living organisms are made of cells, that cells are the basic unit of life, and that new cells arise from existing cells. Spontaneous generation of cells is not part of the theory.

Question 33Core Principles and Frameworks (provisional)

According to the central dogma of molecular biology, information flows from DNA to which molecule before protein is made?

  1. Protein
  2. Lipid
  3. Carbohydrate
  4. RNA Correct answer.

Explanation

The central dogma describes transcription of DNA into RNA and translation of RNA into protein. RNA is the intermediate between DNA and protein.

Question 34Core Principles and Frameworks (provisional)

Which term describes the maintenance of a stable internal environment in an organism?

  1. Osmosis
  2. Metabolism
  3. Adaptation
  4. Homeostasis Correct answer.

Explanation

Homeostasis is the regulation of internal conditions such as temperature and pH within a tolerable range. It involves feedback mechanisms that counteract deviations.

Question 35Core Principles and Frameworks (provisional)

What is the primary mechanism of evolution proposed by Darwin?

  1. Mutation pressure
  2. Genetic drift
  3. Natural selection Correct answer.
  4. Lamarckian inheritance

Explanation

Darwin proposed natural selection as the main mechanism of evolution: heritable variation that affects survival and reproduction becomes more common over generations. Other mechanisms can also cause evolution but were not Darwin's central proposal.

Question 36Core Principles and Frameworks (provisional)

Which class of biological macromolecules includes enzymes?

  1. Carbohydrates
  2. Nucleic acids
  3. Lipids
  4. Proteins Correct answer.

Explanation

Enzymes are proteins that catalyze biochemical reactions by lowering activation energy. Their function depends on their three-dimensional structure.

Question 37Core Principles and Frameworks (provisional)

What is the main purpose of mitosis in multicellular organisms?

  1. Production of gametes
  2. Introduction of genetic variation
  3. Growth and repair of tissues Correct answer.
  4. Reduction of chromosome number

Explanation

Mitosis produces genetically identical diploid cells for growth, tissue repair, and asexual reproduction. Gamete production and chromosome reduction occur in meiosis.

Question 38Core Principles and Frameworks (provisional)

Which gas is released as a byproduct of photosynthesis?

  1. Oxygen Correct answer.
  2. Carbon dioxide
  3. Methane
  4. Nitrogen

Explanation

Photosynthesis uses light energy to convert carbon dioxide and water into sugars, releasing oxygen from the splitting of water. Oxygen is the byproduct.

Question 39Core Principles and Frameworks (provisional)

A researcher tests whether fertilizer affects plant height by giving one group fertilizer and another water. What is the independent variable?

  1. Volume of water administered
  2. Presence of fertilizer Correct answer.
  3. Height of the plants
  4. Type of soil used

Explanation

The independent variable is the factor deliberately manipulated by the researcher, which here is whether fertilizer is present. Plant height is the dependent variable, and other factors should be held constant.

Question 40Core Principles and Frameworks (provisional)

An enzyme-catalyzed reaction is given increasing substrate concentrations while enzyme concentration is held constant. What typically happens initially?

  1. Reaction rate decreases immediately due to inhibition
  2. Rate rises until all enzyme sites are occupied Correct answer.
  3. Enzyme denatures permanently
  4. Reaction rate remains unchanged

Explanation

As substrate concentration increases, more enzyme active sites are occupied and the reaction rate rises. The rate plateaus when the enzyme becomes saturated.

Question 41Core Principles and Frameworks (provisional)

A red blood cell placed in a hypertonic solution will most likely:

  1. Remain unchanged in volume
  2. Shrink as water leaves the cell Correct answer.
  3. Actively pump solutes inward
  4. Swell and burst from water entry

Explanation

In a hypertonic solution, the surrounding solute concentration is higher than inside the cell, so water moves out by osmosis. The cell loses water and shrinks.

Question 42Core Principles and Frameworks (provisional)

In a monohybrid cross between two heterozygous tall pea plants (Tt), what fraction of offspring is expected to be short (tt)?

  1. 3/4
  2. 1/4 Correct answer.
  3. 1/2
  4. All

Explanation

A Tt × Tt cross produces offspring in a 1 TT : 2 Tt : 1 tt ratio. Only the tt genotype expresses the short phenotype, so the expected fraction is 1/4.

Question 43Core Principles and Frameworks (provisional)

During DNA replication, which enzyme unwinds the double helix?

  1. Helicase Correct answer.
  2. Primase
  3. Polymerase
  4. Ligase

Explanation

Helicase separates the two DNA strands by breaking hydrogen bonds between base pairs, creating the replication fork. Other enzymes then synthesize and join new DNA strands.

Question 44Core Principles and Frameworks (provisional)

Which process produces mRNA from a DNA template?

  1. Mutation
  2. Transcription Correct answer.
  3. Translation
  4. Replication

Explanation

Transcription is the synthesis of an RNA molecule using a DNA template. In eukaryotes, the resulting mRNA is processed before translation.

Question 45Core Principles and Frameworks (provisional)

What is a key difference between mitosis and meiosis?

  1. Mitosis produces gametes while meiosis produces somatic cells
  2. Mitosis introduces more genetic variation than meiosis
  3. Meiosis produces haploid cells; mitosis produces diploid cells Correct answer.
  4. Meiosis occurs only in prokaryotes

Explanation

Meiosis reduces the chromosome number by half, producing haploid gametes, while mitosis generally maintains the diploid chromosome number. Meiosis also generates more genetic variation through crossing over and independent assortment.

Question 46Core Principles and Frameworks (provisional)

Allele frequencies in a population remain constant over generations only if certain conditions are met. This principle is known as:

  1. Hardy-Weinberg equilibrium Correct answer.
  2. Gene flow between adjacent populations
  3. Random genetic drift in small populations
  4. Directional natural selection

Explanation

Hardy-Weinberg equilibrium describes the conditions under which allele and genotype frequencies remain stable in a population. Deviations from those conditions indicate that evolutionary forces are acting.

Question 47Core Principles and Frameworks (provisional)

Which type of natural selection favors individuals with extreme phenotypes at both ends of a trait distribution?

  1. Stabilizing selection
  2. Artificial selection
  3. Directional selection
  4. Disruptive selection Correct answer.

Explanation

Disruptive selection favors both extremes and can split a population into distinct phenotypic groups. Directional selection favors one extreme, and stabilizing selection favors the middle.

Question 48Core Principles and Frameworks (provisional)

What is the primary role of antibodies in the immune response?

  1. Producing long-lived memory B cells after infection
  2. Releasing histamine to trigger inflammation
  3. Binding antigens to mark them for destruction Correct answer.
  4. Directly engulfing and digesting pathogens by phagocytosis

Explanation

Antibodies bind specifically to antigens on pathogens or toxins, neutralizing them or marking them for destruction by other immune cells. They do not themselves engulf pathogens.

Question 49Core Principles and Frameworks (provisional)

Which process converts atmospheric nitrogen into a form usable by plants?

  1. Denitrification
  2. Ammonification
  3. Nitrogen fixation Correct answer.
  4. Nitrification

Explanation

Nitrogen fixation converts atmospheric N2 into ammonia or related compounds that plants can use. This is carried out by certain bacteria and archaea, often in symbiotic root nodules.

Question 50Core Principles and Frameworks (provisional)

Why is informed consent important in human-subject research?

  1. It speeds up data collection
  2. It guarantees that participants will never experience any harm
  3. It ensures participants understand risks and can choose freely Correct answer.
  4. It removes the need for ethical review

Explanation

Informed consent respects participant autonomy by ensuring that people understand the study, its risks, and their right to withdraw. It does not eliminate risk or replace ethical oversight.