After suffering a brain injury by falling from a ladder, zack's wife continues to tell the doctor that his personality has changed. he used to be fun loving and carefree, but he is now more critical and yells at his children for seemingly little reason. zack is likely to have suffered damage to the of his cortex

Donald is studying the eating habits of all students attending his school. he samples the population by dividing the students into groups by grade level and randomly selecting a proportionate number of students from each group. he then collects data from the sample. which type of sampling is used? select the correct answer below: systematic sampling convenience sampling stratified sampling cluster sampling