SAMPLE SCOUT KEY
Part II: Identifying Methods
06
An agricultural scientist divides a massive 500-acre cornfield into 100 equal, mapped square plots. She randomly selects 8 of those plots and collects soil samples from every spot in those 8 plots.
Simple Random Systematic Stratified Cluster
Model Justification: The whole geographical plots act as heterogeneous clusters; 8 clusters are selected randomly, and everyone in those plots is tested.
07
A tech firm wants to measure employee remote-work fatigue. The HR director groups staff by departments (Engineering, Sales, HR, Marketing) and then randomly selects 12% of the employees in each department.
Simple Random Systematic Stratified Cluster
Model Justification: Departments form natural strata; HR samples proportionally (12%) from each stratum to ensure all organizational sectors are represented.
08
A university food safety task force assigns a unique sequential number to every student enrolled. They use a random number generator to choose exactly 250 students to interview about campus dining.
Simple Random Systematic Stratified Cluster
Model Justification: The full roster is sample-selected directly via mathematical random number software, giving everyone identical likelihood of selection.
09
Airport security guards want to conduct regular detailed baggage inspections. They line up and decide to screen every 12th passenger who passes through the security metal detector.
Simple Random Systematic Stratified Cluster
Model Justification: The select criterion is built on a simple arithmetic interval pattern (every 12th) applied to a flow of individuals.
10
A state education department is assessing new teacher guidelines. The department randomly selects 12 entire school districts across the state and interviews every teacher in those 12 districts.
Simple Random Systematic Stratified Cluster
Model Justification: The entire school districts represent clusters. 12 whole clusters are drawn at random, and every teacher inside those clusters is analyzed.
Data Detective Series © 2026 Teacher Answer Key — Page 2 of 3
SAMPLE SCOUT KEY
Part III: Final Challenges
11
A music streaming platform analyzes user habits by grouping listeners based on their favorite music genre (Pop, Rock, Hip-Hop, Country), then randomly selects 500 listeners from each of those groups.
Simple Random Systematic Stratified Cluster
Model Justification: The listener pool is split into homogeneous music genres (strata), and random samples of 500 are chosen from within each.
12
To study forest canopy density, researchers divide a regional map into a grid of 1,000 coordinate points. They use a random number table to pick exactly 40 specific coordinates to physically hike to and analyze.
Simple Random Systematic Stratified Cluster
Model Justification: An objective, tabular randomized procedure selects coordinates directly from a master population of possible coordinates.
13
A supermarket chain wants feedback on organic produce. They position an interviewer at the entrance, who is instructed to administer the feedback survey to every 15th shopper who enters the sliding glass doors.
Simple Random Systematic Stratified Cluster
Model Justification: The design dictates a consistent mechanical k-step gap (every 15th shopper) of the inbound retail traffic pattern.
14
A corporation with 80 regional branches studies corporate gym usage. They randomly select 5 complete branch locations and interview every single employee working at those selected locations.
Simple Random Systematic Stratified Cluster
Model Justification: Individual branch offices represent distinct clusters. The company samples whole branches and gathers metrics from everyone inside.
15
In a sleep-aid trial, researchers split volunteers into three age groups (18–34, 35–50, and 51+). They randomly select exactly 40 active participants from each of the three brackets.
Simple Random Systematic Stratified Cluster
Model Justification: The cohort is divided by age groups (strata), and randomized selection is conducted inside each separate stratum.
Data Detective Series © 2026 Teacher Answer Key — Page 3 of 3
