In 67 80, determine whether the given sequence is arithmetic, geometric, or neither. If the sequence is arithmetic, find the common difference; if it is geometric, find the common ratio. If the sequence is arithmetic or geometric, find the sum of the first 50 terms.

Review Controlled experiment as well as observational studies are good methods for collecting data. However, observational studies are not as successful as controlled experiment. In a controlled experiment, the investigator decides who will be in the control group and who will be in the treatment group In an observational study, the subjects assign themselves to one of these two groups. o The studies on The effect of smoking The sex discrimination on graduate admission The racial discrimination in work place The effect of spanking a child (can lower IQ Are some examples of observational studies o In any observ