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### Unit 5: Lesson 4

Topic D: Comparing populations

# Comparing distributions with dot plots (example problem)

Sal examines two distributions in dot plots to draw conclusions about the times of Olympic swimmers. Created by Sal Khan.

## Want to join the conversation?

• Why distribution in dot plot?
• Why am I so confused...?
• Well you could try re-watching the video or looking on articles related to this topic. Feel free to talk abt what your confused on.
Maybe I can help
(1 vote)
• The swimmers had a faster time in the finals? If you do the math the finals averaged 53.18 and the Semi-Finals averaged 53.31. So that answer is incorrect.
~Aubrey
• Actually, in swimming the lowest time wins.
Example: Handsome Jack races from one end to the other. His final score...
17. 18 seconds
Second place...
67. 18 seconds
• The answer to the semifinal round is 53.3375, and the final round is 53.1875, I don't know if I got it right, is it only 0.15 seconds?
• I calculated a difference of 0.25. It seems like you've got the process down but you made a small mistake in your calculation. Nothing to worry about.
• could you explain more this statement "That does look to be true. We see in the semifinals, a lot of the times were clumped up right around here at 53.3 seconds and 53.5 seconds. The high time isn't as high as this time. The low time isn't as low there. So the final round is definitely-- they vary noticeably more"
• Sal means that if you look at the graph for the semifinals, the fastest time recorded isn't as fast as the fastest time for the finals. Same for the slowest time recorded, that's why the final round varies noticeably more in range.
hope this helps!
• why did I understand the video but, then flunk the questions?
• Did you review the video after you flunked the question?
(1 vote)
• why does math suck so bad
• me no like math, why hard?