What is the theoretical probability that an even number will be rolled on a number cube?

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

If a is a nonzero real number then the reciprocal of a is

Find the missing factor. write your answer inexponential form.9^2=9^4×