Using the data file "Stocks" and the first 20 weeks of GoDaddy stock prices, predict the stock price for the 21st week. Compare this with the actual 21st-week stock price (Why is it different?). Identify at least 3 reasons for the difference.

Here is the data are given in data file "stocks"

1 Date Apple GoDaddy CAT J& BerHath S&P500 Dow30 Nasdaq 4/6/2015 127.1 25.29 82.6 102.06 215211 2102.06 18057.65 4995.98 4/13/2015 124.75 25.16 83.28 99.58 212982 2081.18 17826.3 4931.81 4 4/20/2015 130.28 25.63 84.6 101.08 214490 2117.69 18080.14 5092.08 5 4/27/2015 128.95 25.96 87.37 100.13 215800 2108.29 18024.06 5005.39 6 5/4/2015 127.62 24.88 87.31 101.47 222880 2116.1 18191.11 5003.55 7 5/11/2015 128.77 26.51 88.43 102.3 218640 2122.73 18272.56 5048.29 8 5/18/2015 132.54 26.1 88.63 101.35 217000 2126.06 18232.02 5089.36 9 5/25/2015 130.28 26.93 85.32 100.14 214800 2107.39 18010.68 5070.03 10 6/1/2015 128.65 28.69 86.05 98.59 211560 2092.83 17849.46 5068.46 11 6/8/2015 127.17 29.28 87.85 98.35 210760 2094.11 17898.84 5051.1 12 6/15/2015 126.6 31.8 87.52 99.86 212200 2109.99 18015.95 5117 13 6/22/2015 126.75 29.54 86.82 99.64 209900 2101.49 17946.68 5080.51 14 6/29/2015 126.44 27.14 84.38 98.44 205923 2076.78 17730.11 5009.21 15 7/6/2015 123.28 26.98 82.15 99.53 209800 2076.62 17760.41 4997.7 16 7/13/2015 129.62 26.29 83.16 100.08 215960 2126.64 18086.45 5210.14 17 7/20/2015 124.5 26.54 76.1 99.15 212032 2079.65 17568.53 5088.63 18 7/27/2015 121.3 28.44 78.63 100.21 214000 2103.84 17689.86 5128.28 19 8/3/2015 115.52 26.34 77.29 98.85 215463 2077.57 17373.38 5043.54 20 8/10/2015 115.96 26.21 78.49 98.81 213981 2091.54 17477.4 5048.24 21 8/17/2015 105.76 25.1 75 95.56 202500 1970.89 16459.75 4706.04 22 8/24/2015 113.29 25.91 75.95 95.17 205344 1988.87 16643.01 4828.32 23 8/31/2015 109.27 24.69 73.1 91.31 196501 1921.22 16102.38 4683.92 24 9/7/2015 114.21 25.21 72.63 92.93 198329 1961.05 16433.09 4822.34 25 9/14/2015 113.45 24.88 71.86 93.39 192200 1958.03 16384.58 4827.23