Thirty students recorded the colors of their eyes, choosing from the colors brown, blue, green, hazel, and black. This data can be appropriately summarized in a(n)  .

One hundred students are shown an eight-digit number on a piece of cardboard for three seconds and are asked to then recite the number from memory. The process is repeated until   student accurately recites the entire number from memory. The following histogram presents the number of trials it took each student to memorize the number.   How many students memorized the number in three trials or less?

How many values are in the data set whose histogram is shown below ?  

For the class 16.3-23.8, the width is 8.5.

What is the lower class limit in the class 8-12?

A pathogen entering the respiratory tract would encounter which external defense mechanism?

Which of the following choices best describes the primary function of antibodies?

A substance that is too small (low molecular weight) to stimulate antibody production by itself unless it is attached to a larger carrier molecule is called a(an):

Eosinophils are specialized immune cells primarily associated with: 

According to the U.S. Preventive Services Task Force recommendations, which statement about health screening is correct?