Hypothesis: It is hypothesized that Plantago major plants tend to grow abundantly in the soil that is closest to the footpath compared to the soil which is further away from the footpath.

Materials

• Measurement tape
• Pins

Procedure

1. The grassland along a footpath which was traversed by many commuters daily was chosen to carry out the investigation.
2. With the help of the measurement tape, a 30 cm by 30 cm square immediately adjacent to the footpath was marked such that a white pin was pierced into the soil at each of the four corners of the square.
3. The number of Plantago major plants were counted in this first square and noted down.
4. Three squares i.e. 90 cm horizontally away from the first square and perpendicular to the footpath, a fifth square of the same size 30 cm by 30 cm was measured and marked.
5. The number of plants in this square was also counted and noted down. (Figure A)
6. 100 cm vertically away from the first square, another row of five squares was measured and marked in the same manner as in steps 2-5, and the numbers of plants were counted in the first and fifth squares. (Figure A)
7. Three more rows each 100 cm vertically apart and each consisting of five horizontally adjacent squares was marked, and the numbers of plants in first and fifth squares were counted.
8. An attempt was made to keep the measurements, being the controlled variables, as accurate and constant as possible. All the pins were at last removed from the soil.

(Diagram not to scale)                        

Results                                                        

1. Data Collection

Table 1:

2. Data processing and presentation

Null hypothesis: There is no difference in the number of plants in the first square and the fifth square.

In order to prove the presence or absence of any differences as pointed in the null hypothesis, Chi-squared test was carried out.

Number of Groups: 2

Observed frequency (O) in group one: 6+1+2+6+2 = 17

Observed frequency (O) in group two: 0

Expected frequency (E) in group one: 17+0/2 = 8.5

Expected frequency (E) in group two: 0+17/2 = 8.5

Table 2:

X2 = ∑ (O – E) 2/E

X2 = 8.5 + 8.5 = 17

Degrees of freedom: n-1 (number of groups minus one); 2 – 1 = 1

The critical values of chi-square distribution with 1 degree of freedom from the reference table for chi-square test are:

At 5%: 3.84

Conclusion and evaluation: Since the chi-square value i.e. X2 = 17 is higher than the critical values at 5%, therefore, the null hypothesis can be rejected; implying that with 95% certainty there exists a difference between the number of plants that grow immediately adjacent to the sidewalk (first square) and the number of plants that grow further away from the sidewalk (fifth square). A diagrammatic illustration in Figure B clearly indicates this difference. Thereby it could be concluded that the growth of Plantago major is most likely related to the human footsteps, and therefore, the result obtained holds true for the hypothesis made prior to the investigation.

The reason that there were no plants in the squares away from the sidewalk could be due to the fact that the investigation was carried out in early autumn; implying that most plants begin to wither and disappear. More reliable results could be obtained if the experiment is repeated a number of times and data is obtained from various grasslands.