The principal of a small school needs a sample of 20 students, so she goes to the cafeteria and asks every fifth student in line to answer a survey. what kind of sampling is this?

a. simple random sampling
b. stratified random sampling
c. systematic sampling
d. convenience sampling

Consider the linear model for a two-stage nested design with b nested in a as given below. yijk=\small \mu + \small \taui + \small \betaj(i) + \small \varepsilon(ij)k , for i=1,; j= ; k=1, assumption: \small \varepsilon(ij)k ~ iid n (0, \small \sigma2) ; \small \taui ~ iid n(0, \small \sigmat2 ); \tiny \sum_{j=1}^{b} \small \betaj(i) =0; \small \varepsilon(ij)k and \small \taui are independent. using only the given information, derive the least square estimator of \small \betaj(i) using the appropriate constraints (sum to zero constraints) and derive e(msb(a) ).

What is the value of x in the equation 15(x + 4) - 3 = 4.5(x - 2)?

Cavaliers principle states that two solids with equal heights and cross-sectional volumes at every level have equal areas.