Using the same survey methodology: random sample of US residents between the ages of 18 to 75 who registered on the Crest website as a product, Crest wants to divide the research population into heterogeneous groups based on age and gender and then draw a random sample from each of the different groups. Based on this information, what type of sampling method would Crest use to conduct this survey

Stratified sampling

Step-by-step explanation:

Samples may be classified as:

Convenient: Sample drawn from a conveniently available pool.

Random: Basically, put all the options into a hat and drawn some of them.

Systematic: Every kth element is taken. For example, you want to survey something on the street, you interview every 5th person, for example.

Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.

Stratified: Also divides the population into groups. However, then only some elements of the group are surveyed.

In this question:

Population divided into groups, and random samples are drawn from the groups. This is a mark of stratified sampling.

28

Step-by-step explanation:

Replace x for 8 in the equation and solve it normally