England · Pearson EdexcelQ&A
StatisticsQ&A by dot point
A short Q&A bank for every England Statistics syllabus dot point. Each question and answer is drawn directly from our worked dot-point page, so you can scan key concepts before opening the long-form answer.
Probability
- Two-way tables, sample space diagrams, tree diagrams and Venn diagrams for up to three events; mutually exclusive and exhaustive events; the addition law and the multiplication law for independent events.0Q&A pairs
- Formal notation for independent and conditional events; the multiplication law for independent events; the conditional probability formula; dependent events such as selection without replacement.0Q&A pairs
- The probability scale and language of likelihood; calculating theoretical probability; estimating probability from data using relative frequency; experimental probability tending to theoretical as trials increase.0Q&A pairs
- Expected frequency from probability; absolute and relative risk expressed as expected frequencies; comparing experimental data with theoretical predictions to detect bias in the design.0Q&A pairs
Processing, representing and analysing data
- Cumulative frequency diagrams (discrete and grouped); estimating the median, quartiles and percentiles; box plots; comparing distributions using box plots and the interquartile range.0Q&A pairs
- Histograms for continuous data with equal and unequal class widths; frequency density; using area to represent frequency; estimating frequencies within a class; correct use of class boundaries.0Q&A pairs
- Bar charts (including multiple and composite), line graphs, frequency polygons, population pyramids and choropleth maps; representing, interpreting and comparing data sets shown graphically.0Q&A pairs
- Tabulation, tally, two-way tables, pictograms, pie charts, stem and leaf diagrams and Venn diagrams; choosing and justifying an appropriate representation; spotting misleading diagrams.2Q&A pairs
Scatter diagrams and correlation
- Vocabulary of correlation (positive, negative, zero, causation, association, interpolation, extrapolation); describing correlation by inspection as strong or weak; correlation does not imply causation; spurious correlation.0Q&A pairs
- Line of best fit by eye through the double mean point; the regression line y = a + bx; interpreting gradient and intercept; using the line for prediction with awareness of interpolation and extrapolation.0Q&A pairs
- Calculating and interpreting Spearman's rank correlation coefficient; interpreting Pearson's product moment correlation coefficient; the distinction between rank correlation and product moment correlation.0Q&A pairs
Statistical distributions
- Characteristics of a binomial distribution; the notation B(n, p); the conditions for a binomial model; the mean np; calculating binomial probabilities for n up to 10.0Q&A pairs
- Sample means are less spread than individual values; control charts for sample mean, median or range; warning lines at two standard deviations and action lines at three; the action to take when a value falls outside a limit.0Q&A pairs
- Characteristics of a Normal distribution; the notation N(mu, sigma squared); the symmetrical bell shape with equal mean, median and mode; the 68, 95 and 99.7 per cent proportions; conditions for a Normal model.0Q&A pairs
Statistical inference
- The Petersen capture-recapture formula to estimate a population size; the assumptions the method relies on and their appropriateness; the role of sample size in the reliability of the estimate.0Q&A pairs
- Using summary statistics to estimate population characteristics; estimating the population mean from a sample; predicting population proportions; the effect of sample size on reliability and replication.0Q&A pairs
Summarising data
- Mode, median and mean for discrete and grouped data; estimating the mean of grouped data with midpoints; linear interpolation for the median; weighted and geometric mean; effect of changes and transformations on averages.0Q&A pairs
- Range, quartiles, interquartile range, percentiles, interpercentile and interdecile range; choosing an appropriate measure of spread; pairing a measure of spread with a measure of central tendency.0Q&A pairs
- Skewness by inspection and by calculation; interpreting positive and negative skew; identifying outliers by inspection and using the quartile and standard deviation rules; commenting on outliers in context.0Q&A pairs
- Standard deviation for a set of values and for grouped data; using the mean and standard deviation to compare data sets; standardising values with the standardised score to compare across distributions.0Q&A pairs
The collection of data
- Sources of data, reliability and validity, designing questionnaires and data collection sheets, open and closed questions, leading questions, pilots, and cleaning data before processing.0Q&A pairs
- Identifying and controlling extraneous variables, control groups and matched pairs, sources of bias, sensitivity of content, and the random response technique for sensitive questions.0Q&A pairs
- Population, sampling frame and sample; simple random, systematic, stratified, quota, cluster, judgement and opportunity sampling; selecting random members; calculating strata sizes.0Q&A pairs
- The statistical enquiry cycle: planning a hypothesis, recognising constraints, collecting, processing, interpreting and evaluating, with proactive strategies to manage problems.0Q&A pairs
- Types of data: raw, quantitative, qualitative, categorical, ordinal, discrete, continuous, ungrouped, grouped, bivariate and multivariate; primary versus secondary; explanatory and response variables; grouping into class intervals.0Q&A pairs
Time series and index numbers
- Simple index numbers; chain base index numbers; weighted index numbers; the retail price index, consumer price index and gross domestic product; calculating and interpreting index numbers in context.0Q&A pairs
- Rates of change over time including percentage change, births, deaths, house prices and unemployment; calculating crude rates with a given formula; standardised rates at Higher tier; making predictions from rates.0Q&A pairs
- Time series graphs; identifying trends by inspection and by calculating moving averages; plotting a trend line; interpreting seasonal and cyclic variation; using trends and seasonal effects to predict.0Q&A pairs