Researchers once surveyed college students on their Facebook use. The following two-way table displays data for the sample of students who responded to the survey. **How many students in the survey responded that they use Facebook?** [[☃ numeric-input 1]] students Age | Uses Facebook | Does not use Facebook - | :-: |:-: $18$ to $22$ | $78$ | $4$ $23\,\text{+}$ | $70$ | $67$ [//]: # (A. Karpinski and A. Duberstein, “A description of Facebook use and academic performance among undergraduate and graduate students,” paper presented at the American Educational Research Association annual meeting, April 2009. Thanks to Aryn Karpinski for providing us with some original data from the study.)