Answer:
a) Cluster sampling
Step-by-step explanation:
<em>Since here the population is divided into many groups (cluster) and one of these groups is taken as a sample. This type of sampling is called Cluster Sampling.</em>
Further,
In Cluster Sampling the population is distributed into a distinct group called cluster and clusters are chosen as a sample then it is Cluster Sampling.
Multistage Sampling is a complex form of Cluster Sampling. In this sampling population is divided into a different group then one or more groups are randomly selected then again that selected group is divided into a different small group and again one or more these small groups are randomly selected as sample. This process is done many times.
If the sampling is done by any criteria then this type of sampling method is called Systematic Sampling. Like observer is taken every 5th unit as a sample.
If the whole population is divided into many groups(strata) such that between the group units are heterogeneous and within the group units are homogeneous then units are randomly selected from these groups. This type of sampling is called Stratified Sampling.
Answer:
A = 0 +/- nπ radians , where n is an integer.
Step-by-step explanation:
cos 2A = cos^2 A
Use the identity cos 2A = 2 cos^2 A -1 :
2cos^2 A - 1 = cos^2 A
cos^2 A = 1
Cos A = +/-1
When cos A = 1, A = 0 +/- 2nπ radians.
when cos A = -1, A = π +/- nπ radians.
The answer is 735 J
<span>A work (W) is a product of a force (F) and a
distance (d):
W = F · d
</span>
W = ?
F = 245N
d = 3m
W = 245N * 3m
W = 735 J
