Mathletics: How Gamblers, Managers, and Sports Enthusiasts Use Mathematics in Baseball, Basketball, and Football

By Wayne Winston | Go to book overview

40
RATING SPORTS TEAMS

Most gamblers believe that when bookies set point spreads their goal is to have half the money bet on each team. If I bet $10, for example, on a 7.5- point favorite to cover the spread, I win $10 if the team covers but I lose $11 if the favorite does not cover. If the favorite covers the points spread half the time, on average each $10 bet results in an expected profit of (1/2)($10) + (1/2)(—$11) = $—.50. Thus a bettor loses on average $0.50/ $10.50 or $1/21 per dollar bet. Assuming we bet the same amount on each game, to break even we would have to win a fraction p of our bets where p(10) + (1 — p)(—11) = 0. The value p = 11/21 = .524 solves this equation. Thus to win money on average we must beat the point spread at least 52.4% of the time.

Most bookmakers have power ratings on NFL and NBA teams.1 These ratings can be used to set point spreads for which the favorite has approximately a 50% chance of covering the spread. For example, if the Colts have a power rating of + 10 and the Browns have a power rating of —4, we would expect on a neutral field the Colts to win by 10 — (—4) = 14 points. Of course, teams play better at home. Home edges for various sports (based on the last ten years) are 3 points for the NFL, NBA and college football and 4 points for NCAA men's basketball. We will see later in the chapter how to estimate the home edge for a given set of games. Using the NFL home edge of 3 points the bookies would favor the Colts by 14 + 3 = 17 points at home and favor the Colts by 14 — 3 = 11 points at Cleveland. Predictions created from power ratings usually create (in the absence of injuries) a “fair line” in the sense that the favorite and underdog have an equal chance of covering the prediction.

1 In baseball you bet on a team to win. The probability of a baseball team winning depends
heavily on the starting pitchers. We will ignore baseball in our discussions because of this
added complexity.

-266-

Notes for this page

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this book

This book has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this book

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this page

Cited page

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited page

Bookmark this page
Mathletics: How Gamblers, Managers, and Sports Enthusiasts Use Mathematics in Baseball, Basketball, and Football
Table of contents

Table of contents

Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this book

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
/ 358

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.