英文的统计学问题An official from the securities commission estimates

英文的统计学问题
An official from the securities commission estimates that 75% of all investment bankers have profited from the use of insider information.If 15 investment bankers are selected at random from the commission’s registry
a).what is the probability that at most 10 but at least 6 have profited from insider information?
b).what is the probability that more than 6 have profited from insider infromation?
c).what is the probability that at most 9 and more than 14 have profited from insider information?
d).what is the expected number of investment bankers who have profited from the use of insider information?
希望明天天气晴朗 1年前 已收到2个回答 举报

ghwu2008 幼苗

共回答了16个问题采纳率:81.3% 举报

a.
(0.75^6)*(0.25^9)(15C6)+(0.75^7)*(0.25^8)(15C7)+(0.75^8)*(0.25^7)(15C8)+(0.75^9)*(0.25^6)(15C9)+(0.75^10)*(0.25^5)(15C10)=0.3127
b.
1-(0.75^0)*(0.25^15)(15C0)-(0.75^1)*(0.25^14)(15C1)-(0.75^2)*(0.25^13)(15C2)-(0.75^3)*(0.25^12)(15C3)-(0.75^4)*(0.25^11)(15C4)-(0.75^5)*(0.25^10)(15C5)-(0.75^6)*(0.25^9)(15C6)=0.004193
c.
The question does not make any sense.at most 9 and more than 14?
d.
E(x)=np=15*0.75=11.25
You must be taking AP Stats too...well,if you ever need more help,my email is angela3clark@yahoo.com.=) Good luck.

1年前

4

413038353 幼苗

共回答了14个问题 举报

英语等于0分,不好意思

1年前

1
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