Schizophrenia and other psychoses are complex and debilitating diseases, which affect about 2% of the population. Two of the approaches used, as well as in other medical diseases, to reduce clinical heterogeneity among psychoses are categorical and dimensional. The first one assumes that there exist different subgroups within psychosis and the second one assumes that schizophrenia dimensions fall on a dimensional continuum within psychosis. A sample of 660 consecutively admitted patients in Hospital Virgen del Camino (Pamplona, Spain) is available with the following diagnoses: 358 schizophrenic patients, 61 with schizophreni form disorder, 37 with schizoaffective disorder, 64 with bipolar disorder, 24 with delusional disorder, 54 with brief psychotic disorder, and 32 with atypical psychosis. Compute a 95% confidence interval for the proportion of the different types of patients (Cuesta et al., 2007).