Probability receives increasing attention in secondary education because of the need to educate citizens to make decisions in uncertain situations. In this sense, representations used to provide problem data, solve probability problems, and overcome reasoning biases play an important role in probability learning. In particular, tabular representations aid in enumerating the elements of the sample space or analyzing the frequentist approach of probability, among others; however, their apparent simplicity is not free of interpretation difficulties. Thus, we aimed to analyze the tabular representations included in the study of probability in textbooks of the two most recent Spanish curricular guidelines published in 2015 and 2022. We focused on textbooks because of their importance as a didactic resource for students and as a support for teachers’ planning. Moreover, previous research analyzing the presentation of probability in secondary education textbooks is scarce.

Using content analysis, we identified and classified the types of tables in two complete series of secondary education textbooks (19 in total), considering two editorials (Anaya and Santillana). In each textbook, we studied and revised the units dealing with probability several times to ensure the coding reliability. The statistical tables were classified into three types:
a) data tables (the first organization of a data set that contains information on one or more variables without actually forming their distribution);
b) frequency tables (presenting the absolute or relative frequency corresponding to a variable distribution); and
c) two-way tables (representing the modalities of the joint distribution of two variables and in which it is possible to consider the joint, marginal, and conditional distributions).

Considering how publishers deal with the subject in the textbooks, Anaya maintains probability lessons only for three grades (grades 1, 3, and 4 in the previous regulation and grades 2, 3, and 4 in the current regulation), while Santillana includes probabilistic content for all grades in both normative. However, the number of tables was double in Anaya than in Santillana in both regulations.

Regarding tabular language in the probability study, against the previous research recommendations, we found no growth in the number or difficulty of tabular language per course. Finally, both publishers demonstrated a notable presence of two-way tables (approximately 63% of the tables in Anaya and 27% in Santillana under the previous regulation, 76% and 53% under the current regulation, respectively); however, two-way tables were presented in all textbooks by Anaya in both regulations, but restricted to the last grades by Santillana, mainly in the current regulation. Noteworthy, no two-way tables were displayed to show the sample space of a compound experiment in Santillana in any regulation. Thus, we showed a poverty of tabular representations in the study of probability in the sample texts analyzed, which goes against the incrementality required in learning the language of probability. Even when the study of statistics immediately precedes the probability study in the textbooks, it has not been considered to reinforce the learning of statistical tables within the topic of probability; mainly, taking into account their interest in introducing the frequentist meaning of probability by frequency tables or the study of conditional and compound probability by contingency tables.

Keywords: Tabular language, probability, secondary education, textbook.