Question

The dot plots below show the scores for a group of students for two rounds of a quiz: Which of the following inferences can be made using the dot plots? The range of round 2 is greater than the round 1 range. Round 2 scores are higher than round 1 scores. Round 1 scores are lower than round 2 scores. There is no overlap between the data.

Answer 1

Answer: Choice A) round 2 has larger range

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Explanation:

• Choice A is true. The range is the difference of the max and min. Round 1 has a range of 5-4 = 1, while round 2's range is 5-1 = 4. Round 2 has a larger range of scores. We don't really need to do any kind of math here. We can simply spot that round 2 has its dots more spread out compared to round 1, so round 2 must have the larger range.
• Choice B is somewhat true. If we compare a score of 4 in round 1 to a score of 5 in round 2, then round 2 has a higher score. But we could easily flip things around. So saying one round has higher scores than the other is not particularly meaningful in this scenario. I would say it all depends on how you phrase the problem carefully. In any event, I would say that choice B is false since we can't definitively say it's true.
• Choice C is a similar story as choice B, just flip things around. So I'd say this is false too. We would need all of the dots of round 1 to be to the left of all the dots of round 2, in order for choice C to be a true statement. Because there's overlap, we run into a problem.
• Choice D is false because there is overlap for scores 4 and 5. In other words, both dot plots have dots over "4" and over "5". These are the scores the dot plots share in common.