Business statisticsLesson 1 of 2 in the course Linear Regression and Correlation

Linear Equations: Slope, Intercepts, and Business Models

5 flashcards · 5 quiz questions · 5 match pairs · 4 fill-in sentences · English

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Summary

Linear equations describe relationships between two variables using a straight line. In this lesson, you will learn how to interpret the equation y=a+bxy=a+bx, identify its independent and dependent variables, understand slope and the y-intercept, and use the equation to model real-world costs and earnings.

Here, aa and bb are constants. The variable xx is the independent variable: its value is chosen or observed. The variable yy is the dependent variable: its value is determined by the equation and depends on xx.

All flashcards

What is the general form of a linear equation with one independent variable?
y=a+bxy=a+bx, where aa and bb are constants, xx is independent, and yy depends on xx.
What does the slope bb represent?
It represents the constant change in yy for each one-unit increase in xx, and determines the line's direction and steepness.
What does the y-intercept aa represent?
It is the value of yy when x=0x=0; the graph crosses the y-axis at (0,a)(0,a).
How can you graph a linear equation?
Substitute several values of xx to find corresponding yy values, plot the resulting ordered pairs, and draw the straight line through them.
What are the slope and intercept in C=31.50+32hC=31.50+32h?
The slope is 3232 dollars per hour, the added cost for each hour. The intercept is 31.5031.50, the one-time fixed charge.

Quiz questions

  1. Which symbol denotes the dependent variable in y=a+bxy=a+bx?Answer: yy
  2. In the equation y=7+4xy=7+4x, what is the slope?Answer: 44
  3. Where does the graph of y=−1+2xy=-1+2x cross the y-axis?Answer: At (0,−1)(0,-1)
  4. A service charges a $20 fixed fee plus $12 per hour. Which equation gives total cost CC for hh hours?Answer: C=20+12hC=20+12h
  5. Does a linear equation relating two variables by itself prove that one variable causes changes in the other?Answer: No; the equation alone does not establish causation.

Based on Introductory Business Statistics 2e by Alexander Holmes, Barbara Illowsky, Susan Dean (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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