A researcher was interested in the effect of winning a lottery on happiness. To examine this issue, he measured the happiness of 100 people who had won a lottery prize of five million dol-lars or more with a comparison group of 100 people who played the lottery but had never won. He found that there was no significant difference in overall happiness between the two groups and concluded that "Winning the lottery appears to have no appreciable impact on people's level of overall happiness." What type of design is this (explain your choice)? Is the researcher's conclusion justified? Why or why not