Two Graphs About Screen Time
A class reads a report on screen time. The report states: "In a survey of 400 students, 55% said they use screens more than three hours a day. Of those, 60% said they also read for fun at least once a week." The report concludes: "Heavy screen use does not stop students from reading." A second paragraph says the survey was done online during a school break. The class must judge whether the conclusion follows from the numbers.
1. Does the conclusion follow from the data? Explain using the numbers.
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It does not fully follow. The survey has 400 students, and 55% is 220 students who use screens more than three hours a day. Of those 220, 60% is 132 who also read weekly. So 132 of 220 heavy screen users read for fun weekly. But that means 88 of them do not. Also, the report never gives the reading rate for students with low screen use. Without that comparison, we cannot say heavy screen use "does not stop" reading. A careful answer does the two calculations and names the missing comparison.
2. The survey was done online during a school break. How could that affect the results?
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Doing the survey online during a break could affect who answered. Students without reliable internet or devices may be left out, so the 400 may not represent the school. Screen time during a break may also be higher or lower than during school weeks, so the 55% may not match a normal week. Reading for fun may also change on a break. These are problems with how the data was collected, not with the math. A strong answer says the direction of the effect is uncertain: the numbers could be too high or too low, so we should treat the conclusion as weak.
3. Rewrite the conclusion so it is supported by the survey.
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A supported version would be: "In this online survey of 400 students during a school break, 55% reported more than three hours of daily screen use, and 60% of that group also reported reading for fun at least weekly." This version states who was surveyed, when, and what was reported, and it makes no claim about cause. It also avoids saying screen use "does not stop" reading, because the survey only shows that many heavy users also read. The rewrite keeps the numbers and drops the unsupported general claim.