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

sunsunsun1225

Hi can anyone show how to use second derivative test to prove that the deviation of linear regression has a local minimum but not a maximum? thanks

  • one year ago
  • one year ago

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

    The second derivative test \[f_{aa} f_{bb} - f_{ab}^2\]reduces to 4n^2( VAR(X)) where VAR(x) = \[1/n \sum_{i=1}^{n} (x_i - \mu)^2\] and \[\mu = 1/n \sum_{i=1}^n x_i\]. This is always positive, hence not a saddle point. \[f_{aa} = 2 \sum_{i=1}^n x_i^2\] which is always positive, hence a local minimum.

    • one year ago
  2. sunsunsun1225
    Best Response
    You've already chosen the best response.
    Medals 0

    Thank you so much

    • 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.