已知某个小麦品种的株x(单位:cm)服从正态分布,N(66.33,2.882),现在随机抽取一株,问(1)株高在60c

2个回答

  • (1)P(X<60)

    =Φ[(60-66.33)/2.882]

    =Φ(-2.20)

    =1-Φ(2.2)

    =1-0.9861

    =0.0139

    (2)P(X>69)

    =1-P(x≤69)

    =1-Φ[(69-66.33)/2.882]

    =1-Φ(0.93)

    =1-0.8238

    =0.1762

    (2)P(60≤X≤69)

    =1-P(X<60)-P(X>69)

    =1-0.0139-0.1762

    =0.8099