[ 285 ] Life Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • A coffee retailer wants to know whether customers prefer brand A or brand B coffee. So, he sets up a blind taste test. He prepares pots of coffee with equal volumes using the same amount of coffee, either brand A or brand B. The coffees are brewed at the same temperature and the same time. The retailer knows which pot contains brand A and which contains brand B. He gives the pots to a clerk. A clerk pours two sample cups of equal volume for each customer, one from each pot. The pots of coffee are not labeled and the clerk does not know which coffee she is serving. For 100 customers, she has each customer taste each sample cup of coffee and write which choice he or she preferred. The clerk tallies the choices and gives the tally to the coffee retailer. Identify the controlled and uncontrolled factors in the experiment. Assign the correct variables into each box: Independent Variable Dependent Variable Controls • amount of coffee in each pot • coffee brand served • coffee temperature • coffee brewing time • volume of coffee pots • customer’s preferred coffee brand • amount of coffee served • The clerk does not know what brand she is serving.