In a study of motivation and learning, a teacher employed the following research strategy: Students were asked what teaching methods were most motivating. The teacher then looked back at her test scores to investigate whether the test scores were higher for the more motivating sessions compared with the less motivating sessions. The teacher found that, indeed, student achievement rose as the teacher used more and more motivating methods. From this result, she decided to use the more motivating methods all the time. Was her decision to use more motivating methods correct? Why or why not?