Thế nào là một ước lượng hiệu quả? Cho X1,X2,... là một mẫu ngẫu nhiên có cỡ mẫu n(n>30) từ một tổng thể với E(X)=μ và phương sai D(X)= σ^2 (x_1+x_2+x_3)/3 và tổng x là những ước lượng không lệch hay có lệch của μ
Ước lượng nào ở câu a là ước lượng hiệu quả
Xây dựng khoảng ước lượng đối xứng cho trung bình tổng thể

The following function returns a string of length n whose characters are all 'x'. give the order of growth (as a function of n) of the running time. recall that concatenating two strings in java takes time proportional to the sum of their lengths. public static string f(int n) { if (n == 0) return ""; if (n == 1) return "x"; return f(n/2) + f(n - n/2); } options: a) constant b) logarithmic c) linear d) linearithmic e)quadratic f)cubic g) exponential

[a] create a class called “cycle” which has two instance integer variables as properties, “numberofwheels” and “weight.” create a constructor with two parameters, using the same variable names in the parameter list. assign each variable to numberofwheels” and “weight” respectively. write a separate application to test the class and display its properties. note: do not change the names of the instance variables or the variables listed in the constructor’s parameter list. [b] edit your class cycle by adding a default constructor which will assign the default values of 100 to represent the numberofwheels, and 1000 to represent the weight, by invoking a call to the other constructor. modify your application created in [a] to test the class.

Janice recently received her college degree and is looking for a job. she is worried that since she just finished school, she will be required to repay her perkins and direct subsidized loans immediately. janice pulls out the paperwork she signed and reviews it again for repayment information. after reading all of the information, janice discovers that