A value that does not change

The table below shows the surface area y, in square feet, of a shrinking lake in x days:

Sindrei [870]

The scatter graph of the data is shown in the first picture below

The 'line of best fit' shows a negative gradient

Part A: The most likely coefficient is -0.98.
If the coefficient is -1, then each point would be exactly on the straight line (which they are not as shown on the graph). The graph however still shows a strong negative coefficient. It can be seen from the close distance of each point from the line of best fit. So -0.5 and -0.02 is unlikely as they show weak negative correlation

Part B: Refer to the second picture to see the horizontal and vertical distance between day 15 and day 20

The horizontal distance is 5 units
The vertical distance is read between 61 and 71.5, hence it's 10.5
The slope = Vertical distance ÷ Horizontal Distance = 10.5÷5 = 2.1
The 'downhill' slope shows a negative gradient, hence the value of the slope is -2.1
The value of the slope shows that the surface area of the lake shrinks by 2.1 for every one day

Part C: The data in the table represents the relation between two variables. Since one variable doesn't cause the change in the other variable, the data table represents correlation rather than a causation.

3 0

4 years ago

Graph a line that contains the point (-5,-3) and has a slope of -2

Tpy6a [65]

Answer:

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Step-by-step explanation:

Graph (-5,-3) and use the slope, -2, to find another point. -2 can also be written as $-\frac{2}{1}$

$\frac{rise}{run} =\frac{-2}{1}$ and $\frac{rise}{run} =\frac{2}{-1}$ **

Use both. This works because either way, they will lie on the same line with the same slope. So, starting at (-5,-3), go down two points (-)* and to the left 1 (+)*, then, starting at (-5,-3) again, go up two points (+)* then to the right 1 point (-)*.

* If the number is negative, you either go down or to the right. If the number is positive, you go up and to the left.

**Rise over run refers to the change in the y-axis and the change in the x-axis: $\frac{rise}{run} =\frac{y-axis}{x-axis}$ . Only one number is negative because, if both were negative, that would make a positive number, but the slope is -2, not 2.