Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

LyraElizabethAdams

PLEASE HELP!!!!!!!!! (Medal will go to best answer.) Use the standard deviation to identify any outliers in the given data set: {3,4,5,6,8,9,10,30} Please explain why there is or isn't an outlier and how you'd determine if there is one or not. Thank you! =)

  • one year ago
  • one year ago

  • This Question is Closed
  1. LyraElizabethAdams
    Best Response
    You've already chosen the best response.
    Medals 0

    By the way - the variance is: 66.035

    • one year ago
  2. nbouscal
    Best Response
    You've already chosen the best response.
    Medals 1

    First, find the standard deviation of the data set. To do this, find the mean, then find the distance each point is from the mean, square and sum those distances, and square root the total. Once you have that, check how many standard deviations the data points are from the mean. There's no set definition for what makes a point an outlier; your class may have specified a number of standard deviations that qualifies. Inevitably, with this data set, the answer will be that 30 is an outlier, but you'll need to show why. Edit: Since you have the variance, you can just take the square root of the variance to find the standard deviation.

    • one year ago
  3. LyraElizabethAdams
    Best Response
    You've already chosen the best response.
    Medals 0

    Wow! Thanks so much. I found that the variance is: 8.13 - my class didn't specify if this would classify it as an outlier. What do you think?

    • one year ago
  4. LyraElizabethAdams
    Best Response
    You've already chosen the best response.
    Medals 0

    *sorry I meant that 8.13 is the Standard Deviation

    • one year ago
  5. LyraElizabethAdams
    Best Response
    You've already chosen the best response.
    Medals 0

    BTW - the mean of the original data set was: 9.375

    • one year ago
  6. nbouscal
    Best Response
    You've already chosen the best response.
    Medals 1

    Well, since you know the standard deviation, and you know the mean, you can find how many standard deviations away from the mean each point is. At some cutoff, you'll say that a point is an outlier if it's more than a certain number of standard deviations away from the mean. With this data set, 30 is more than 2 standard deviations away from the mean, so it's definitely an outlier.

    • one year ago
  7. LyraElizabethAdams
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay, perfect! Thank you so much! I really appreciate your thoroughness! If I could give you another medal, I would. :)

    • one year ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.