Question

1. What is the correlation between the selling price and square footage (three decimal places)?

House 2 3 10 Appraise Selling Squar Bedr Bathr d Value Price e Feet ooms ooms 119,370 121,870 2050 4 5 148,930 150,250 2200 4 4 130,390 122,780 1590 3 3 135,700 144,350 1860 3 3 126,300 116,200 1210 2 3 137,080 139,490 1710 3 2 123,490 115,730 1670 3 3 150,830 140,590 1780 3 4 123,480 120,290 1520 132,050 147,250 1830 2 3 148,210 152,260 1700 3 3 139,530 144,800 1720 3 4 114,340 107,060 1670 3 4 140,040 147,470 1650 3 3 136,010 135,120 1610 2 1 140,930 140,240 1570 3 4 132,420 129,890 1650 4 5 118,300 121,140 1640 3 4 122,140 111,230 1420 2 3 149,820 145,140 2070 4 3 128,910 139,010 1610 2 3 134,610 129,340 1910 4 4 121,990 113,610 1410 2 2 150,500 141,050 1860 4 3 142,870 152,900 1990 4 3 155,550 157,790 2270 5 4 128,500 135,570 1965 4 4 143,360 151,990 1820 3 3 119,650 120,530 1650 122,570 118,640 1470 2 2 145,270 149,510 1850 4 3 149,730 146,860 2170 4 4 147,700 143,880 1930 3 3 117,530 118,520 1380 2 1 140,130 146,070 1810 3 4 136,570 135,350 1760 3 4 130,440 121,540 1530 2 3 118,130 132,980 1700 3 2 130,980 147,530 1980 4 4 131,330 128,490 1590 2 2 15 16 17 18 19 20 21 41 141,100 141,930 1740 42 117,870 123,550 1730 43 160,580 162,030 2100 44 151,100 157,390 2040 45 120,150 114,550 1730 46 133,170 139,540 1680 47 140,160 149,920 2050 48 124,560 122,080 1750 49 127,970 136,510 1870 50 101,930 109,410 1330 51 131,470 127,290 1700 52 121,270 120,450 1460 53 143,550 151,960 1910 54 136,890 132,540 1610 55 106,110 114,330 1470 56 137,540 141,320 1810 57 134,330 83,760 1650 58 127,590 118,200 1520 59 137,440 140,200 1920 60 114,090 113,550 1410 61 145,460 156,520 2030 62 141,900 137,350 1950 63 116,340 110,610 1340 64 149,200 153,690 1850 65 141,810 153,330 1780 66 116,440 111,950 1440 67 137,740 143,460 2040 68 144,700 142,130 2160 69 149,660 155,460 2170 70 118,170 135,440 1710 71 137,660 127,300 1640 72 119,700 113,770 1380 73 143,120 141,110 2100 74 129,910 130,080 1610 75 141,780 139,350 1950 76 159,190 160,030 2080 77 156,130 152,840 1960 78 126,720 122,270 1920 79 133,220 145,880 1920 80 118,090 115,470 1490 3 2 3 2 5 6 44 2 1 2 2 4 4 3 3 4 3 2 3 3 3 2 3 3 3 2 1 2 1 3 4 2 2 2 1 45 2 1 3 3 34 2 1 34 3 2 2 1 44 5 4 43 23 3 2 2 1 5 6 2 2 4.4 5 4 3 2 4 4 4 3 2 1 81 141,630 135,720 1600 2 1 82 138,560 136,160 1650 3 2 83 134,100 144,920 1890 4 5 84 132,240 131,290 1620 3 4 85 145,820 138,530 1820 3 4 86 127,150 124,050 1750 3 2 87 105,070 107,900 1460 2 1 88 127,200 123,450 1530 3 2 89 111,560 111,700 1540 2 3 90 150,410 145,140 1950 3 2 91 129,150 120,440 1480 3 2 92 130,310 136,870 2050 4 4 93 129,230 140,300 1660 3 2 94 105,060 113,780 1540 2 3 95 134,210 141,230 1720 3 4 96 109,250 104,830 1400 2 1 97 127,350 118,790 1578 3 4 98 104,010 112,040 1700 3 3 99 133,940 137,270 1880 4 5 100 141,130 145,710 1850 3 4 101 136,530 138,380 1430 2 3 102 118,040 109,460 1390 2 1 103 153,700 144,680 2130 4 5 104 126,310 133,270 1890 4 4 105 134,020 133,270 1640 2 3 106 141,560 150,380 2070 3 3 107 142,960 135,260 1810 3 2 108 118,530 112,600 1460 2 1 109 121,590 114,230 1410 2 2 110 146,400 153,240 2190 4 3 111 141,250 125,890 1580 3 4 112 130,730 135,620 1840 3 3 113 132,650 138,820 1930 3 3 114 125,570 129,430 1930 4 5 115 125,740 136,450 1820 3 4 116 120,220 126,740 1480 2 1 117 128,290 130,090 1600 2 1 118 136,890 132,680 1880 3 2 119 142,430 142,890 1780 3 2 120 119,310 127,040 1920 3 2 121 120,370 131,450 1830 4 3 122 118,830 114,570 1470 2 3 123 124,490 129,560 1690 3 4 124 140,570 149,550 1930 4 5 125 133,620 140,820 1970 2 3 126 105,050 111,550 1530 2 2 127 147,090 142,760 2030 5 6 128 115,430 124,250 1830 3 3 129 125,370 132,320 2070 3 4 130 115,970 121,450 1630 2 3 131 125,210 132,450 1580 3 2 132 130,370 135,830 1760 3 4 133 119,750 125,760 1810 4 5 134 120,930 125,840 1710 3 2 135 126,800 135,320 1890 3 3 136 118,820 120,140 1640 2 1 137 144,080 147,530 2010 4 4 138 142,490 144,940 1730 3 3 139 140,550 136,010 1770 4 3 140 130,360 119,330 1750 4 5 141 124,270 131,150 1660 3 3 142 167,730 172,360 2510 5 6 143 129,190 137,170 1700 2 3 144 125,180 124,710 1660 3 4 145 157,510 148,650 2110 4 5 146 126,670 128,520 1430 2 2 147 137,570 132,020 1710 4 5 148 133,460 128,030 1580 2 1 23 24 25 26 31 32 38 39 40

2. What is the intercept for the regression line predicting selling price from square footage (no decimal places)?Selling_Price = Intercept + Slope * Square_Footage

3. What is the slope for the regression line predicting selling price from square footage (three decimal places)?Selling_Price = Intercept + Slope * Square_Footage

4. What is the predicted selling price for a 2400 square foot house (no decimal places)?Selling_Price = Intercept + Slope * Square_Footage

Answer 1

1.

The correlation coefficient is obtained in excel using the function =CORREL(). The screenshot is shown below,

X f r =CORREL(A2:A149,B2:B149) 1 Selling Price Square Feet 1,21,870 2050 1,50,250 2200 Excel function 0.6142 CORREL(A2:A149,B2:B149) Correlation

Correlation coefficient = 0.614

2.

The intercept of the regression line is obtained in excel using the function =INTERCEPT(). The screenshot is shown below,

X f r =INTERCEPT(A2:A149,B2:B149) C D E B 1 Selling Price Square Feet 1,21,870 2050 1,50,250 2200 1,22,780 1590 Excel function Correlation 0.6142 CORREL(A2:A149,B2:B149) Intercept | 47238.35 INTERCEPT(A2:A149,B2:B149)

Intercept = 47238

3.

The slope of the regression line is obtained in excel using the function =SLOPE(). The screenshot is shown below,

x fc =SLOPE(A2:A149,B2:B149) 1 Selling Price Square Feet 1,21,870 2050 1,50,250 2200 1,22,780 1590 1,44,350 1860 Correlation Intercept Slope Excel function 0.6142 CORREL(A2:A149,B2:B149) 47238.35 INTERCEPT(A2:A149,B2:B149) 48.3287|SLOPE(A2:A149,B2:B149)

Slope = 48.329

4.

The regression line is,

Selling Price = 47238 + 48.329 Square Footage

For square foot = 2400

Selling Price = 47238 + 48.329 x 2400 = 163227