Kal is a novice researcher who is conducting his own study as part of his Masters' program requirements. In Kal's study, the more people studied Spanish as a second language, the more they understood the language, but only if they had Spanish-speaking friends, which is an interaction that Kal was not expecting in the data. What type of statistical test should Kal conduct next? post hoc analyses Pearson r tests marginal means planned comparisons