Researchers conduct a study to determine whether happiness among students differs across four different schools.From each school, a sample of 20 people were chosen, but the sample was stratified by grade 'lst grade, 2nd grade, 3rd grade, 4th grade]. Fiye people were chosen in each grade category in each school. Mean happiness score in each school is reported below. City Sample Mean happiness socre A 2.1 B 41] (3 SI) D 3.1 Now the researchers want to consider how grade affect mean happiness score AND they suspect that the effect of grade may change between schools. How might they address this research questions? Conduct two separate on way ANOVAs for grade and school and compare the result Conduct a two-way ANOVA with an interaction term for school and happiness scores Conduct a two-way ANOVA with an interaction term for grade and school d. Conduct a two-way ANOVA with an interaction term for grade and happiness scores. I think answer is C. Is my answer correct? pas-m