The following table relates to the tourist arrivals during 1990 to 1996 in Botswana:
Years: 1990 1991 1992 1993 1994 1995 1996
Tourist’s arrivals: 18 20 23 25 24 28 30
Fit a straight line trend by the method of least squares and estimates the number of tourists that would arrives in the year 2000.
Let "X=" the number of years since 1990
"\\bar{x}=\\dfrac{1}{n}\\displaystyle\\sum_{i=1}^nx_i=\\dfrac{21}{7}=3"
"\\bar{y}=\\dfrac{1}{n}\\displaystyle\\sum_{i=1}^ny_i=\\dfrac{168}{7}=24"
"SS_{xx}=\\displaystyle\\sum_{i=1}^nx_i^2-\\dfrac{1}{n}\\bigg(\\displaystyle\\sum_{i=1}^nx_i\\bigg)^2=91-\\dfrac{21^2}{7}=28"
"SS_{yy}=\\displaystyle\\sum_{i=1}^ny_i^2-\\dfrac{1}{n}\\bigg(\\displaystyle\\sum_{i=1}^ny_i\\bigg)^2=4138-\\dfrac{168^2}{7}=106"
"SS_{xy}=\\displaystyle\\sum_{i=1}^nx_i\\displaystyle\\sum_{i=1}^ny_i-\\dfrac{1}{n}\\bigg(\\displaystyle\\sum_{i=1}^nx_i\\bigg)\\bigg(\\displaystyle\\sum_{i=1}^nx_i\\bigg)"
"=557-\\dfrac{21(168)}{7}=53"
Based on the above calculations, the slope "m" and the y-intercept "n" are obtained as follows:
"y=\\bar{y}-m\\bar{x}=24-\\dfrac{53}{28}(3)=\\dfrac{513}{28}=18.3214"
So the trend line is
The number of tourists that would arrives in the year 2000 is
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