HP 40gs HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010.p - Page 148

In the MATH menu, Probability section (see page 208), there is a function called UTPC (Upper-Tailed Probability Chi-squared) which will give the critical X2 probability for a supplied number of degrees of freedom and a value. In this case we would like the value for a given probability so we will enter the formula into the Solve aplet. Change to the NUM view, enter the known parameters of D=4 and P=0.05, and for the critical X2 value. Since our value of 16.387 is larger than the critical value of 9.488 we conclude that we must reject the null hypothesis and judge that the observed values do not follow this binomial distribution and hence that the coin is probably biased. This does not say that it is not binomially distributed; just not with those parameters. Importing from a frequency table The import ( ) facility of the Inference aplet has a small weakness in that it can't import from paired columns defining a frequency table. For example, suppose we use columns C1 and C2 to define a frequency table, ensuring that it is registered in the SYMB view as shown right. If you now change to the NUM SETUP view of the Inference aplet and try to use the import facility you will find that you can import the mean and standard deviation from either column C1 or C2 but not from both at once. What's needed, of course, is a way to expand the paired frequency table columns into a single column listing all values. You can, of course, create the expanded columns by hand but the program on the next page will do this for you. 148