Question: 在2025年07月17日-2025年09月20日，海尔智家的价格有多少次跌破20日指数移动平均线？（平滑系数 alpha 取 2 / (n + 1)；从前 4n 个数据开始计算；初始值用首个数据点）使用不复权价格，写出指标公式，搜集原始数据，计算得出答案，保留四位小数。注意列出原始数据和关键计算过程。
Formula: EMA_t = \alpha * P_t + (1 - \alpha) * EMA_{t-1}，\alpha = 2 / (n + 1)
Data:
date,close,low,high,open
2025-03-20,27.68,27.68,28.15,28.1
2025-03-21,27.5,27.38,28.05,27.57
2025-03-24,28.29,27.6,28.47,27.71
2025-03-25,28.2,28.19,29.07,28.22
2025-03-26,27.93,27.8,28.28,28.05
2025-03-27,28.06,27.6,28.14,27.8
2025-03-28,27.16,26.92,27.8,27.8
2025-03-31,27.34,26.93,27.76,27.0
2025-04-01,26.95,26.88,27.48,27.4
2025-04-02,27.02,26.92,27.22,26.98
2025-04-03,26.2,26.1,26.54,26.5
2025-04-07,23.58,23.58,24.87,24.48
2025-04-08,24.75,23.6,24.75,23.66
2025-04-09,25.04,23.88,25.04,24.26
2025-04-10,25.51,25.06,25.87,25.87
2025-04-11,25.07,24.66,25.48,25.48
2025-04-14,24.77,24.74,25.18,25.15
2025-04-15,24.77,24.42,25.0,24.62
2025-04-16,24.99,24.2,24.99,24.7
2025-04-17,24.65,24.47,24.7,24.7
2025-04-18,24.55,24.41,24.74,24.5
2025-04-21,24.78,24.5,24.89,24.52
2025-04-22,24.68,24.56,24.86,24.69
2025-04-23,24.88,24.85,25.25,24.87
2025-04-24,24.78,24.68,24.98,24.9
2025-04-25,25.02,24.79,25.05,24.85
2025-04-28,24.96,24.82,25.14,25.03
2025-04-29,25.04,24.71,25.04,24.92
2025-04-30,24.79,24.75,25.36,25.03
2025-05-06,25.12,24.77,25.15,24.9
2025-05-07,25.18,25.08,25.69,25.62
2025-05-08,25.41,25.05,25.5,25.14
2025-05-09,25.39,25.17,25.53,25.36
2025-05-12,26.13,25.77,26.23,25.77
2025-05-13,25.99,25.96,26.52,26.5
2025-05-14,26.13,25.85,26.29,25.95
2025-05-15,26.02,25.88,26.18,26.13
2025-05-16,25.68,25.5,25.96,25.9
2025-05-19,25.72,25.56,25.79,25.59
2025-05-20,26.3,25.6,26.39,25.73
2025-05-21,26.22,26.12,26.49,26.25
2025-05-22,26.19,26.01,26.3,26.07
2025-05-23,25.76,25.76,26.31,26.13
2025-05-26,25.51,25.44,25.85,25.75
2025-05-27,25.22,25.2,25.62,25.58
2025-05-28,25.11,25.02,25.39,25.28
2025-05-29,25.4,25.23,25.73,25.24
2025-05-30,25.04,25.03,25.32,25.3
2025-06-03,24.73,24.65,25.01,24.95
2025-06-04,24.84,24.76,24.92,24.8
2025-06-05,24.71,24.7,24.92,24.85
2025-06-06,24.83,24.66,24.87,24.76
2025-06-09,24.98,24.77,25.1,24.9
2025-06-10,24.88,24.71,25.27,25.0
2025-06-11,25.15,24.85,25.3,24.87
2025-06-12,24.97,24.85,25.09,25.09
2025-06-13,24.44,24.1,24.8,24.8
2025-06-16,24.42,24.27,24.49,24.35
2025-06-17,24.91,24.46,24.95,24.48
2025-06-18,25.0,24.83,25.19,24.86
2025-06-19,24.7,24.62,25.07,24.95
2025-06-20,24.65,24.6,24.83,24.7
2025-06-23,24.55,24.25,24.67,24.47
2025-06-24,24.72,24.55,24.92,24.55
2025-06-25,24.93,24.65,24.95,24.78
2025-06-26,24.72,24.71,25.01,24.93
2025-06-27,24.84,24.62,25.04,24.8
2025-06-30,24.78,24.74,24.97,24.88
2025-07-01,24.76,24.71,24.82,24.8
2025-07-02,25.58,24.73,25.69,24.77
2025-07-03,25.75,25.33,25.78,25.59
2025-07-04,25.85,25.55,26.0,25.69
2025-07-07,25.61,25.43,25.91,25.85
2025-07-08,25.52,25.45,25.7,25.66
2025-07-09,25.29,25.25,25.73,25.55
2025-07-10,25.25,25.16,25.46,25.31
2025-07-11,25.35,25.26,25.76,25.3
2025-07-14,25.41,25.35,25.62,25.41
2025-07-15,25.8,25.43,25.91,25.53
2025-07-16,25.68,25.62,26.03,25.83
2025-07-17,25.81,25.63,26.1,25.68
2025-07-18,25.79,25.63,25.99,25.88
2025-07-21,26.05,25.78,26.05,25.85
2025-07-22,26.81,25.95,26.85,26.04
2025-07-23,27.5,26.81,27.58,26.81
2025-07-24,27.41,27.04,27.56,27.5
2025-07-25,25.83,25.8,26.49,26.45
2025-07-28,25.65,25.6,25.93,25.83
2025-07-29,25.41,25.32,25.69,25.61
2025-07-30,25.58,25.3,25.82,25.43
2025-07-31,24.84,24.75,25.57,25.57
2025-08-01,24.9,24.79,25.07,24.92
2025-08-04,24.96,24.77,25.02,24.79
2025-08-05,25.03,24.83,25.12,25.01
2025-08-06,25.23,24.91,25.25,25.04
2025-08-07,25.06,24.95,25.21,25.19
2025-08-08,25.12,25.0,25.37,25.06
2025-08-11,25.11,24.98,25.2,25.14
2025-08-12,25.53,25.17,25.87,25.18
2025-08-13,25.5,25.41,25.9,25.67
2025-08-14,25.51,25.46,25.8,25.5
2025-08-15,25.46,25.2,25.74,25.46
2025-08-18,25.39,25.39,25.71,25.51
2025-08-19,25.2,25.2,25.83,25.57
2025-08-20,25.3,24.91,25.3,25.28
2025-08-21,25.59,25.12,25.73,25.32
2025-08-22,25.78,25.55,25.83,25.68
2025-08-25,26.19,25.79,26.24,25.79
2025-08-26,26.26,26.02,26.49,26.2
2025-08-27,25.78,25.78,26.52,26.26
2025-08-28,26.0,25.61,26.12,25.77
2025-08-29,26.26,26.23,27.16,26.6
2025-09-01,25.95,25.94,26.8,26.49
2025-09-02,26.3,25.74,26.4,25.99
2025-09-03,26.19,26.0,26.58,26.35
2025-09-04,25.69,25.48,26.14,26.11
2025-09-05,26.46,25.65,26.52,25.7
2025-09-08,26.44,26.34,26.82,26.39
2025-09-09,26.93,26.36,27.0,26.58
2025-09-10,26.58,26.51,26.88,26.83
2025-09-11,26.62,26.2,26.63,26.54
2025-09-12,26.19,26.13,26.75,26.74
2025-09-15,26.0,25.9,26.21,26.15
2025-09-16,25.92,25.74,26.1,26.03
2025-09-17,26.78,25.91,26.79,25.91
2025-09-18,26.05,25.93,26.94,26.89
2025-09-19,26.32,25.88,26.44,26.05

Indicator data:
date,20日,close
2025-04-17,25.889160231762492,24.65
2025-04-18,25.761621162070828,24.55
2025-04-21,25.668133432349798,24.78
2025-04-22,25.57402548641172,24.68
2025-04-23,25.507927821039175,24.88
2025-04-24,25.438601361892587,24.78
2025-04-25,25.398734565521863,25.02
2025-04-28,25.35695032118645,24.96
2025-04-29,25.32676457631155,25.04
2025-04-30,25.275644140472355,24.79
2025-05-06,25.2608208889988,25.12
2025-05-07,25.253123661475104,25.18
2025-05-08,25.26806426514414,25.41
2025-05-09,25.27967719227327,25.39
2025-05-12,25.360660316818674,26.13
2025-05-13,25.420597429502607,25.99
2025-05-14,25.488159579073788,26.13
2025-05-15,25.53881104773343,26.02
2025-05-16,25.552257614615957,25.68
2025-05-19,25.56823307989063,25.72
2025-05-20,25.637925167520095,26.3
2025-05-21,25.693360865851517,26.22
2025-05-22,25.740659831008514,26.19
2025-05-23,25.742501751864847,25.76
2025-05-26,25.720358727877716,25.51
2025-05-27,25.672705515698887,25.22
2025-05-28,25.61911451420376,25.11
2025-05-29,25.59824646523197,25.4
2025-05-30,25.54508013520988,25.04
2025-06-03,25.46745345566608,24.73
2025-06-04,25.407695983697884,24.84
2025-06-05,25.341248747155227,24.71
2025-06-06,25.2925583902833,24.83
2025-06-09,25.262790924542035,24.98
2025-06-10,25.226334646014223,24.88
2025-06-11,25.219064679727154,25.15
2025-06-12,25.195344234038853,24.97
2025-06-13,25.123406687939916,24.44
2025-06-16,25.056415574802784,24.42
2025-06-17,25.042471234345378,24.91
2025-06-18,25.038426354883914,25.0
2025-06-19,25.006195273466396,24.7
2025-06-20,24.972271914088644,24.65
2025-06-23,24.9320555413183,24.55
2025-06-24,24.91185977547846,24.72
2025-06-25,24.913587415909085,24.93
2025-06-26,24.89515051915584,24.72
2025-06-27,24.88989808876005,24.84
2025-06-30,24.879431604116235,24.78
2025-07-01,24.868057165628976,24.76
2025-07-02,24.935861245092884,25.58
2025-07-03,25.013398269369752,25.75
2025-07-04,25.09307462466787,25.85
2025-07-07,25.142305612794743,25.61
2025-07-08,25.178276506814292,25.52
2025-07-09,25.188916839498646,25.29
2025-07-10,25.194734283355917,25.25
2025-07-11,25.209521494464877,25.35
2025-07-14,25.228614685468223,25.41
2025-07-15,25.28303233447125,25.8
2025-07-16,25.32083877880732,25.68
2025-07-17,25.36742556177805,25.81
2025-07-18,25.407670746370613,25.79
2025-07-21,25.468844961001984,26.05
2025-07-22,25.59657401233513,26.81
2025-07-23,25.777852677827024,27.5
2025-07-24,25.933295279938736,27.41
2025-07-25,25.923457634230285,25.83
2025-07-28,25.89741405001788,25.65
2025-07-29,25.85099366430189,25.41
2025-07-30,25.825184743892184,25.58
2025-07-31,25.731357625426263,24.84
2025-08-01,25.652180708718998,24.9
2025-08-04,25.586258736460046,24.96
2025-08-05,25.533281713940042,25.03
2025-08-06,25.504397741183848,25.23
2025-08-07,25.462074146785387,25.06
2025-08-08,25.42949565661535,25.12
2025-08-11,25.399067498842463,25.11
2025-08-12,25.411537260857468,25.53
2025-08-13,25.419962283632945,25.5
2025-08-14,25.428537304239327,25.51
2025-08-15,25.43153375145463,25.46
2025-08-18,25.427578156078,25.39
2025-08-19,25.40590404597533,25.2
2025-08-20,25.39581794635863,25.3
2025-08-21,25.414311475276854,25.59
2025-08-22,25.449138953821915,25.78
2025-08-25,25.519697148696018,26.19
2025-08-26,25.59020218215354,26.26
2025-08-27,25.608278164805583,25.78
2025-08-28,25.645585006252674,26.0
2025-08-29,25.704100719942893,26.26
2025-09-01,25.727519698995952,25.95
2025-09-02,25.782041632424907,26.3
2025-09-03,25.8208948102892,26.19
2025-09-04,25.808428637880702,25.69
2025-09-05,25.870483053320633,26.46
2025-09-08,25.92472276252819,26.44
2025-09-09,26.02046345181122,26.93
2025-09-10,26.07375264687682,26.58
2025-09-11,26.125776204317123,26.62
2025-09-12,26.13189275628692,26.19
2025-09-15,26.119331541402453,26.0
2025-09-16,26.10034758507841,25.92
2025-09-17,26.165076386499514,26.78
2025-09-18,26.154116730642418,26.05
2025-09-19,26.1699151372479,26.32

Answer: 7.0