Answer:
B. Stratified random sample is the correct answer
Answer:
B. A teacher compares the pre-test and post-test scores of students
Step-by-step explanation:
the answer is true, because it is a good example to compare the tests between students, we know that a matching pair design is a random model and is used when the experiment allows grouping subjects in pairs based on a variable and each pair will receive randomly a different handling, the answer A is not true because in the example all students are uniformly averaged and the variable is not correlated with subgroups, option c is incorrect because the variable was not randomized and generates classification bias and the option d is incorrect because the teacher compares a small sample as her class with a score of a total sample, but does not intervene on her students when selecting the corresponding group
Answer:
the answer is x=6 or x=-16
