# How does mowing or not mowing effect the petiole heights of white clover as measured by the height of the petiole of individual clover heights on a School field?

by lizzielunn817gmailcom (student)

Biology IA

Petiole Heights of White Clover

2013

Design

Aim

To investigate the effect of regular mowing on the petiole height of white clover.

Research Question

How does mowing or not mowing effect the petiole heights of white clover as measured by the height of the petiole of individual clover heights on a Kristin field?

Variables

Independent Variable –

Mowed or Unmowed

Dependant Variable

Height of Petiole

Results

Raw Data Table showing petiole heights (cm) of 50 white clover samples from unmown and mown areas.

Processed Data Table showing mean petiole heights of 50 white clover samples from unmown and mown areas.

Note: Processed data was put to the same number of decimal places as raw data

Calculations:

From:

From:

A T Test has been conducted to determine whether there is a marked difference in the heights of white clover petioles in mown and unmown areas,

Null hypothesis: there is no significant statistical difference between the heights of petioles of white clover in unmown and mown areas.

Alternative hypothesis: there is a significant statistical difference between the heights of petioles of white clover in unmown and mown areas.

Calculating the degrees of freedom:

(sample size) – (the number of samples) = degrees of freedom

50+50 – 2 = 98

df= 98
Therefore critical t value 1.99

From:

Calculated t value = 6.31 (2dp)

Critical t value = 1.99

Our calculated t value of 6.31 is greater than the critical t value of 1.99. This means there is a significant difference between the two means, and therefore there is a significant difference in the heights of the white clover petioles in the mown verses unmown areas.

Graph showing the mean petiole heights of 50 white clover samples from unmown and mown areas

Comment on Graph:

My bar graph shows that as the heights of clover petioles in unmown areas were greater with a mean of 103 than the petiole heights of clover in mown areas with a mean of 42. The error bars were calculated to show one standard deviation either side of the mean, displaying where 68% of the data lay. My error bars are extremely large.

Conclusion and Evaluation

Conclusion

In my experiment I investigated the effect of mowing on petiole heights of white clover, by sampling petiole heights in unmown and mown areas.

From my results I can infer that mowing had a significant effect on the petiole height of white clove. The mean petiole heights of the unmown areas was considerably higher at 103cm than the mean petiole heights in unmown areas at 43cm. This indicates that mowing does cause a decrease in petiole height.

My data was imprecise as indicated by the large standard deviation/error bars. Because our sample size ...