tw1d | teachware quantlet tw1d shows a histogram of user defined data and offers interactive visual analysis of this data by means of box plots (for mean and median) and QQ-plots. Transformations may be applied to the data in order to study the change in distribution and box plots. |
twaremain | loads necessary quantlets in order to execute the teachware tware.lib. |
twaretest | Executes some tests for the quantlets defined in the teachware tware.lib. |
twboxcox | allows to find interactively the best parameter for your data for a Box-Cox transformation. |
twboxcoxintroduction | generates the introductory text for twboxcox |
twboxcoxloop | main loop for twboxcox |
twclt | teachware quantlet twclt shows a discrete four point distribution and simulates repeated sampling from this apparently non normal distribution. The variation of the observed mean values around the true mean value (standardized by scale) is shown in a plot. The user may interactively change the number of samples and thereby study the effect of the central limit theorem (CLT). |
twlinreg | teachware quantlet twlinreg gives visual insight into how least squares simple linear regression works, and the relationship between the regression of Y on X, X on Y, and total regression. |
twnormalize | teachware quantlet twnormalize shows the distribution of binomials B(n1, p), B(n2, p) and B(n3, p) with increasing n1, n2, n3. One may shift the distribution by the mean value and divide by the standard deviation in order to study the normalizing effect. In addition a normal density may be graphically overlaid. |
twpearson | teachware quantlet twpearson gives a visual demonstration of the form of the Pearson correlation coefficient. In particular, it shows why the product moment gives a measure of "dependence", and why it is essential to "normalize", i.e. to subtract means, and divide by standard deviations, to preserve that property. |
twpvalue | teachware quantlet twpvalue computes the p-value of a B(n, p) distribution |
twrandomsample | teachware quantlet twrandomsample asks for a distribution of the numbers {1, 2, 3, 4} displays a bar chart of the entered values and calculates a test for H0: p{2,3} = 0.5, the hypothesis of uniform distribution. |
twskew | teachware quantlet shows effects on skewness and kurtosis by contamination of a normal distribution |
twtest | teachware quantlet shows error type I and II in testing simple hypotheses |