Informal inference with the DBM/OVS rule for larger samples
education
Random samples of 100 students were taken from each of two Wellington secondary schools, and each student's home-to-school commute distance (km) was recorded. Figure 1 shows box plots of the two samples.
| School | n | Min | Q1 | Median | Q3 | Max |
|---|---|---|---|---|---|---|
| P | 100 | 0.4 | 3 | 5.2 | 8 | 24 |
| Q | 100 | 0.6 | 4 | 5.6 | 9 | 27 |
Box plots of home-to-school commute distance (km) for random samples of 100 students from School P and School Q; both are right-skewed with long upper whiskers and the boxes overlap heavily.Facts you may need
(a)
Use Figure 1 to calculate the distance between the medians (DBM), the overall visible spread (OVS) and the ratio DBM/OVS.
(b)
Can you claim that students at School Q tend to live further from school than students at School P? Explain.
(c)
Would the conclusion change if the same summary values had come from samples of 1000 students per school? Explain.
