Sheila bought a box of 25 headbands. When she arranged the headbands by color, she saw that 4 were green, 4 were red, 13 were blue, and 4 were pink. What is the percent of blue headbands she bought?

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .