SL 4.1  Concepts of population, sample, random sample, discrete and continuous data.  Reliability of data sources and bias in sampling 

              Interpretation of outliers. Sampling techniques and their effectiveness. 

SL 4.2  Presentation of data (discrete and continuous): frequency distributions (tables). 

             Histograms. Cumulative frequency; cumulative frequency graphs; use to find median, quartiles, percentiles, range and IQR. 

             Production and understanding of box and whisker diagrams. 

SL 4.3  Measures of central tendency (mean, median and mode). Estimation of mean from grouped data. Modal class. 

             Measures of dispersion (interquartile range, standard deviation and variance). 

             Effect of constant changes on the original data. Quartiles of discrete data. 

SL 4.4  Linear correlation of bivariate data. Pearson’s product-moment correlation coefficient, r. 

             Scatter diagrams; lines of best fit, by eye, passing through the mean point.

             Equation of the regression line of y on x. Use of the equation of the regression line for prediction purposes. 

             Interpret the meaning of the parameters, a and b, in a linear regression y = ax + b. 

SL 4.5  Concepts of trial, outcome, equally likely outcomes, relative frequency, sample space (U) and event.

             The probability of an event A is P(A) = n(A) n(U) . The complementary events A and A′ (not A). Expected number of occurrences 

SL 4.6  Use of Venn diagrams, tree diagrams, sample space diagrams and tables of outcomes to calculate probabilities. 

              Combined events: P(A ∪ B) = P(A) + P(B) − P(A ∩ B). Mutually exclusive events: P (A ∩ B) = 0 

              Conditional probability: P(A|B) = P(A ∩ B) P(B) .  Independent events: P(A ∩ B) = P(A)P(B) 

 SL 4.7  Concept of discrete random variables and their probability distributions. Expected value (mean), E X for discrete data. Applications. 

SL 4.8  Binomial distribution. Mean and variance of the binomial distribution. 

SL 4.9  The normal distribution and curve. Properties of the normal distribution. Diagrammatic representation. 

              Normal probability calculations. Inverse normal calculations 

SL 4.10  Spearman’s rank correlation coefficient, rs . 

               Awareness of the appropriateness and limitations of Pearson’s product moment correlation coefficient and Spearman’s rank correlation coefficient, and the effect of outliers on each. 

SL 4.11 Formulation of null and alternative hypotheses, H0 and H1 . Significance levels. p -values. 

              Expected and observed frequencies. 

               The χ 2 test for independence: contingency tables, degrees of freedom, critical value. The χ 2 goodness of fit test. 

                The t -test. Use of the p -value to compare the means of two populations. Using one-tailed and two-tailed tests.