Final answer:
The y-intercept of y=-4x+2.3 is 2.3, which is where the line crosses the y-axis. In the context of a best-fit line, such as ŷ= -173.51 + 4.83x from a regression analysis, the y-intercept is -173.51, representing the expected value of y when x is zero.
Step-by-step explanation:
The y-intercept of a linear equation is the value of y when x equals zero. It is the point where the line crosses the y-axis. To find the y-intercept of the equation y=-4x+2.3, you can set x to 0 and solve for y. Thus the y-intercept for this equation would be 2.3, as no multiplication by x will affect y when x is 0.
When looking at an example of a line of best fit, the y-intercept represents the starting point of the data when x is 0. In real-world scenarios, sometimes x=0 may not exist or make sense, as in the case with years or other quantities that cannot be zero. For example, in a best-fit line given by the equation ŷ= -173.51 + 4.83x, the y-intercept would be -173.51, which describes the best expected value of y when x is zero.