Wanting to study the effect of exercise on preventing the common cold, a researcher collects 500 test subjects and randomly assigns them to a treatment group instructed to exercise and a control group instructed to not exercise. He later records the number of colds for each group. This is an example of: Group of answer choices linear regression independence an observational study an experiment

What is the base of 1/9 to the power of 2

Write the pair of fractions as a pair of fractions with a common denominator

Aretha wanted to gather data about the cost of local bowling leagues in her area. she plotted the data and determined that the average bowling league costs consist of a one-time registration fee and a monthly fee modeled by the equation y = 15x + 20. identify and interpret the y-intercept in this model. the y-intercept is 20. this is the cost per month. the y-intercept is 20. this is the cost of registration. the y-intercept is 15. this is the cost of registration. the y-intercept is 15. this is the cost per month.