Which action carries a risk most similar to purchasing stock in a company? investing a portion of one's savings in a mutual fund
moving money from one's savings account to a certificate of deposit
setting one's budget so that expenses are exactly the same as income
having money deducted from one's paycheck monthly for government bonds

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

they can increase to boost the enonomy.