Aspire Mountain Academy
  • Home
  • About
  • Courses
  • Contact

Identifying and interpreting critical R values

1/16/2018

0 Comments

 

Intro

Howdy!  I am Professor Curtis of Aspire Mountain Academy here with more statistics homework help.  Today we're going to learn how to identify and interpret critical R values.  Here's our problem statement: For a data set of chest sizes (distance around chests in inches) and weights (pounds) of 12 anesthetized bears that were measured, the linear correlation coefficient is R = 0.873.  Use the table available below to find the critical values of R based on a comparison of the linear correlation coefficient R and the critical values.  What do you conclude about a linear correlation?

Part 1: Identify the critical R values

OK, so here we have an icon where we can access the table of critical values for R.  So we click that.  Here's our table of critical R values.  We need to find the number of pairs of data that we have, and you're given that in the problem statement right up here where it says “12 anesthetized bears,” so 12 is the number that we want to look for.  Here's the number 12 in the table of critical R values.  Corresponding with 12 is 0.576.

Now keep in mind that you have two critical values: one positive and one negative.  Only the positive one is listed here in the table.  So we go to put our answer in.  I'm going to start by putting in this plus-or-minus sign.  You could actually list the answers separately; I think it would take it that way as well — this one negative and then comma and then the other one positive.  But I like to make it easy and not type so much.  So I'm just going to put in a plus or minus sign and then the value from the actual R table.  Well done!

Part 2: Interpret the critical R values

Now, the next part of the problem: “Since the correlation coefficient R is” and then there's a drop down menu — “in the left tail below the negative critical value,” “in the right tail above the positive critical value,” “between the critical values.”  So in order to understand where we're at, it's helpful to draw a number line with your critical values and the value of R generated by your data.  To help us with that, I've actually produced something of a number line here in Excel.

So here we can put in our critical R values.  So we have one that's negative and one that's positive.  Now the question is “Where does our R value lie?”  0.873 lies in this region here, which is a region of acceptance.  So here in this first drop down menu in our answer fields, we're going to select “in the right tail above the positive critical value.”  And we're in a region of acceptance, so there is sufficient evidence to support the claim of a linear correlation.  Excellent!

And that's how we do it at Aspire Mountain Academy.  Be sure to leave your comments below and let us know how good a job we did or how we can improve.  And if your stats teacher is boring or just doesn't care to help you learn stats, go to aspiremountainacademy.com where you can find out more about accessing our lecture videos or provide feedback on what you'd like to see.  Thanks for watching!  We'll see you in the next video.
0 Comments



Leave a Reply.

    Author

    Frustrated with a particular MyStatLab/MyMathLab homework problem?  No worries!  I'm Professor Curtis, and I'm here to help.

    Archives

    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018

    RSS Feed

Stats

Lecture Videos
Homework Help
Problem Index

Company

About
The Company
Courses

Support

Contact
FAQ
Terms of Use
© COPYRIGHT 2018-2020. ALL RIGHTS RESERVED.
Aspire Mountain Academy is a division
of Aspire Mountain Media LLC,

  • Home
  • About
  • Courses
  • Contact