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## Measurement & Data - Statistics & Probability 218-221

### Unit 1: Lesson 10

Shape of data distributions

# Shapes of distributions

Some distributions are symmetrical, with data evenly distributed about the mean. Other distributions are "skewed," with data tending to the left or right of the mean. We sometimes say that skewed distributions have "tails.".

## Want to join the conversation?

• So I'm a bit confused. We say skewed to the left, that means that means that most of the data is towards the left or the right?
• This was really bothering me, too, Jono, and I really appreciated your question. I was just about to post the same thing myself when I saw your post. Then today I was watching Sal's video on comparing distribution means. At around in the video, Sal is talking about an outlier, and he mentions that it skews the data, it drags the mean upward. Then it suddenly all made sense. The data in the tail is off centered from the normal distribution, and it is literally skewing the mean in that direction. Anyway, it made a lot more sense to me when I saw that.

Here's the url for the video in case anyone wants to see it:

• my favorite part was when he burped
• how does this look like an armadillo? looks more like a slug.
• if it is approximately symmetrical, wouldn't it be left-tailed and right-tailed?
(1 vote)
• If you think of it like a pyramid the very top will be symmetrical. IF you have both a right and left tail. I know its confusing.
• What is approximately symmetrical mean?
• Almost, but not completely symmetrical.

An approximately symmetrical distribution is a distribution that isn't very clearly left- or right-tailed.
• I'm confused about the tails and skewed to the left and the right.
• if the mean is on the right is it skewed to the right
• So confused.
3 questions.

1) How can a graphical display be skewed.
2) How do you ensure data isn’t skewed?

Multiple Choice

Which statement describes a cause of skewed data?

a) a sample with not enough observations from the population being measured
b) a random collection of data from the population being measured
c) an inclusive sample that includes all subsets of a population being measured
d) a sample that excludes subjects that are not part of the population being measured

Thank you so much for your help!
• 1) It can be skewed meaning that there are more bars to one side of the highest bar
2) Make sure that both sides of the Largest bar are around the same size
3) I think the answer will be B
Hope this helped!