Suppose that you have just read a careful statistical study of the effect of advertising on the demand for cigarettes. Using data from New York during the 1970s, the study concluded that advertising on buses and subways was more effective than print advertising. Use the concept of external validity to determine if these results are likely to apply to Boston in the 1970s; Los Angeles in the 1970s; New York in 2010. The results are likely to apply to Los Angeles in the 1970s, but not to Boston in the 1970s or to New York in 2010. The results are likely to apply to New York in 2010, but not to Boston in the 1970s or to Los Angeles in the 1970s. The results are likely to apply to Boston in the 1970s, but not to Los Angeles in the 1970s or New York in 2010. O The results are likely to apply to any city in the United States regardless of location and year.