Erica is a marketing researcher involved in improving retail store layouts. She would like to know the order in which various types of products are purchased by customers. She also wants to find out what type of assistance is required by the customers while purchasing products. The best method for Erica to collect this data would be by: Group of answer choices observation. telephonic surveys. voluntary mail-back questionnaires. Delphi technique.

Astudy was interested in determining if eating milk chocolate lowered someone's cholesterol levels.ten people's cholesterol was measured. then, each of these individuals were told to eat 100g of milk chocolate every day and to eat as they normally did. after two weeks, their cholesterol levels were measured again. is there evidence to support that their cholesterol levels went down? how should we write the alternative hypothesis? (mud = the population mean difference= before - after)a. ha: mud = 0b. ha: mud > 0c. ha: mud < 0d. ha: mud does not equal 0