Question

classify the sample as random, systematic, stratified, or cluster.
mail carriers of a large city are divided into four groups according to gender (male or female) and according to whether they walk or ride on their routes. then 10 are selected from each group and interviewed to determine whether they have been bitten by a dog in the last year.
this represents a select sample.
random
systematic
stratified
cluster

Explanation:

Stratified sampling divides the population into subgroups (strata) and then selects a sample from each stratum. Here, mail - carriers are divided into four groups (strata) based on gender and mode of travel (walk or ride). Then, a fixed number (10) is selected from each group. This matches the definition of stratified sampling. In random sampling, each individual has an equal chance of being selected without prior grouping. In systematic sampling, individuals are selected at regular intervals. In cluster sampling, the population is divided into clusters and a sample of clusters is selected, not a sample from each subgroup as here.

Answer:

stratified