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Friday, October 18, 2019

Weekend HW!

Weekend HW (lots of writing/interpreting):

1.) Describe the association between "number of missed classes" and "exam score." -- this is on the paper we had with our "notes examples" about cucumbers and ankle range of motion. Or, here's the context:

2.) Textbook Page 189 - 193 : 11a, 13abc, for 13's context also interpret the yintercept, 35cef
  • For 13c this is called a "residual"-- for this homework just worry about the math
  • For 35cef you'll need to find the equation using your graphing calculator (x = fat, y = calories)
  • Period H: Here's some help with interpreting the y-intercepts since we didn't get to it in class:
    • Remember, the y intercept occurs whenever the x = 0
    • We just want to take this idea that "x = 0" and turn it into the given context
    • For example--back to ankle range of motion and balance scores...
      • The yint = -1.993, so "when x = 0, y = -1.993." 
      • In context, "when ankle range of motion (x) = 0, balance score (y) = -1.993"
      • Sometimes the y-intercept has an unrealistic interpretation--if so, we have to comment on that; in this case, the y-intercept is unrealistic because a balance score cannot be negative!
      • Read the full interpretation in the image below...
3.) ALWAYS CHECK YOUR ANSWERS!
  • Here's the answer to the "describe the association" question:
    • "Based on the scatterplot the association between number of missed classes and exam score is roughly linear, negative, and pretty strong with a correlation of -0.79; generally, as the number of missed classes increases, exam score decreases."
  • Check the back of the book for the textbook stuff....
    • However, any interpretations of slope/yint MUST start with "THE MODEL PREDICTS," which is not done in the back of the book.
  • Here's the answer to "interpret y intercept" (question I added) for the context in 13:
    • "The model predicts that if a house has a size of 0 square feet its predicted price is about 47.82 thousand dollars. This is unrealistic because a house would not exist if it were 0 square feet."
We will have a chapter 7 quiz to start class on Tuesday!
  • Open Ended Section:
    • Describe an association
    • Maybe an open ended like today's stamp (identify mistakes with statements about r, hypothesize about a lurking variable)
  • Vocab Section:
    • Scatterplot
    • Explanatory (Variable)
    • Response (Variable)
    • Lurking Variable
    • Describe an association (what do we describe?)
    • Correlation
      • Also be sure to know the "facts about correlation"
    • Positive Association 
    • Negative Association
    • Y-Hat
If you were out today we discussed how to interpret slope and y-intercept--there are some notes to get before this, but here are the end products for our interpretations:



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