单项选择题 Suppose there are two risky assets: Security 1 has expected return of 15% and standard deviation of 20%, security 2 has expected return of 10% and standard deviation of 25%, and the correlation of security 1 with security 2 is 0.90. Calculating the expected return and standard deviation of portfolio with security 1 and security 2 when the weight of security 1 is 0.8. A、The expected return is 0.14 and standard deviation is 0.265B、The expected return is 0.14 and standard deviation is 0.206C、The expected return is 0.12 and standard deviation is 0.225D、The expected return is 0.12 and standard deviation is 0.265
单项选择题 以下不是学生的本质特点
单项选择题 保存断肢的适宜温度是()