Question

The trend line estimates that the price was $432 in November 2007 and $80 in September 2011. (That is an interval of 46 months.) Use this information to determine the slope of the trend line. Be careful about the sign. (Round your answer in dollars per month to two decimal places.)

Answer 1

slope = -7.65 per month

Step-by-step explanation:

given data

2007 price p1 = $432

2011 price p2 = $80

time t2 = 46 months

solution

we consider here starting time t1 = 0 when price $432

so here slope will be

slope =
`(p2-p1)/(t2-t1)` .....................1

put here value and we will get

slope =
`(80-432)/(46-0)`

slope = -7.65 per month