Perhaps you should try some spelling variations:
"tres modelos estadisticos methods." » "tres metodos estadisticos methods.", "tres modelos estadisticas metodos.", "tres modelos estadisticas datos.", "tres modelos estadisticas medicas.", "los modelos estadisticos methods.", "de modelos estadisticos methods.", "en modelos estadisticos methods."
"procesos control statistical methods." » "process control statistical methods.", "proceso contra statistical methods.", "procesos contables statistical methods.", "procesos control statistics methods.", "procesos control estadisticas methods."

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