According to the New York Times, the number of people receiving food stamps incr
ID: 3114298 • Letter: A
Question
According to the New York Times, the number of people receiving food stamps increased in the early 90’s, but then decreased later in the 90’s. Observe the table below.
Year
1990
1992
1994
1996
1998
Average Monthly Participants
(millions of people)
20.0
25.2
27.3
25.4
19.8
A. Identify and interpret the horizontal intercepts. Discuss the reasonableness of these values in the context of the problem.
B. State the practical domain and range in the context of the problem.
Year
1990
1992
1994
1996
1998
Average Monthly Participants
(millions of people)
20.0
25.2
27.3
25.4
19.8
Explanation / Answer
Clearly the no. of participants are decreasing year on year.
Horizontal intercept is nothing but the root of the equation i.e. the x-value where y is 0.
If we consider the year as independent variable and participants as dependent variable and build a linear regression model, following equation will come out (use excel or any regression tool)
participants = 43.38 - 0.01*(year)
year at which participatns are 0 from above equation is : 43.48/0.1 = 4348.
It means the horizontal intercept is 4348 year.
B.
4348 is very very far right now.
Also the model and trend will definately change over the years. The model which has been built on taking into consideration 10 years of data can not be used for predciting 2000 years of results. So I think it is best the model is used for predicting similar range of years for which data was modelled which is more like 50 years.
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