In: Statistics and Probability
5. You are given the following table.
| X | Y | 
| 1,000 | 500 | 
| 3,000 | 400 | 
| 7,000 | 750 | 
| 12,000 | 1,000 | 
| 15,500 | 1,200 | 
| 17,000 | 1,000 | 
| 17,500 | 1,800 | 
| 21,000 | 2000 | 
| 22,800 | 2,200 | 
| 23,000 | 3,000 | 
a. Decide which variable should be the independent variable and which should be the dependent variable.
b. Draw a scatter plot of the data.
c. Does it appear from inspection that there is a relationship between the variables? Why or why not?
d. Calculate the least-squares line. Put the equation in the form of: ŷ = a + bx.
e. Find the correlation coefficient. Is it significant?
f. Find estimated total values for column Y for 16,000, 24,000, and 36,000 16,000= 24,000= 36,000=
g. Does it appear that a line is the best way to fit the data? Why or why not? h. Are there any outliers in the data?
i. Based on these results, what would be the probate fees and taxes for an estate that does not have any assets?
j. What is the slope of the least-squares (best-fit) line? Interpret the slope.
5)
X: independent
Y : dependent
................
b)

c)
there appear to be linear , positive relation between x and y
...........
d)
| ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
| total sum | 139800 | 13850 | 573936000 | 6310250.0 | 53587000.00 | 
| mean | 13980.00 | 1385.00 | SSxx | SSyy | SSxy | 
sample size ,   n =   10  
       
here, x̅ = Σx / n=   13980.00   ,
    ȳ = Σy/n =  
1385.00  
          
       
SSxx =    Σ(x-x̅)² =   
573936000.0000      
   
SSxy=   Σ(x-x̅)(y-ȳ) =  
53587000.0          
          
       
estimated slope , ß1 = SSxy/SSxx =  
53587000.0   /   573936000.000  
=   0.0934
          
       
intercept,   ß0 = y̅-ß1* x̄ =  
79.7216          
          
       
so, regression line is   Ŷ =  
79.7216   +   0.0934  
*x
..........................
e)
correlation coefficient ,    r = Sxy/√(Sx.Sy)
=   0.8904
correlation hypothesis test      
Ho:   ρ = 0  
Ha:   ρ ╪ 0  
n=   10  
alpha,α =    0.05  
correlation , r=   0.8904  
t-test statistic = r*√(n-2)/√(1-r²) =   
    5.534
DF=n-2 =   8  
p-value =    0.0006  
Decison:   p value < α , So, Reject
Ho  
................
f)
Predicted Y at X=   16000   is  
           
   
Ŷ =   79.72161   +  
0.093368   *   16000   =  
1573.602
Predicted Y at X=   24000   is  
           
   
Ŷ =   79.72161   +  
0.093368   *   24000   =  
2320.543
Predicted Y at X=   32000   is  
           
   
Ŷ =   79.72161   +  
0.093368   *   32000   =  
3067.483
..............
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