Joanne Chan 12C

Size of Allium cepa cells and Ovibos moschatus Oculi cells: Data collection and processing

Raw data

Table 1: Longest length recorded of Allium cepa cells and Ovibos moschatus Oculi cells Length of Allium cepa cells/ m - ±5.0| Diameter of Ovibos moschatus Oculi cells/ m - ±5.0| 330.0| 25.0|

360.0| 30.0|

320.0| 30.0|

280.0| 40.0|

300.0| 40.0|

350.0| 30.0|

300.0| 30.0|

290.0| 30.0|

420.0| 20.0|

280.0| 40.0|

310.0| 20.0|

320.0| 30.0|

180.0| 20.0|

250.0| 20.0|

150.0| 30.0|

Observations:

The appearance of the Allium cepa cells through the microscope was more of a regular, rectangular shape in brown colour. The colour of the cell was due to the iodine solution used to stain. As the size of the Allium cepa cells was bigger, the nucleus and cell wall of the cells could also be spotted through the microscope. On the other hand, the cells of Ovibos moschatus Oculi were in an irregular shape with much smaller size. Thus, the nucleus of the cell could not be spotted. The Ovibos moschatus Oculi cell was in blue colour because of the methylene blue added.

Processed data

Table 2: Mean, median, mode and standard deviation of Allium cepa cells and Ovibos moschatus Oculi cells | Allium cepa cells| Ovibos moschatus Oculi cells|

Mean / m| 296.0| 29.0|

Median / m| 300.0| 30.0|

Mode / m| 320.0| 30.0|

Standard deviation | 66.7| 7.1|

Formula used for calculating standard deviation

Allium cepa cells:

=√ (61220/14)

=66.7(1d.p.)

Ovibos moschatus Oculi cells:

=√ (710/14)

=7.1(1d.p.)

Formula used for calculating standard deviation

Allium cepa cells:

=√ (61220/14)

=66.7(1d.p.)

Ovibos moschatus Oculi cells:

=√ (710/14)

=7.1(1d.p.)

The data from table 1 showed all 15 different samples of Allium cepa cells and Ovibos moschatus Oculi cells with an uncertainty of ±5m. The average of these data are calculated and recorded in table 2, the mean size of the Allium cepa cells are much larger than Ovibos moschatus Oculi cells. However, the Ovibos moschatus Oculi cells have a similar size with smaller deviation from the mean. The sizes of Allium cepa cells are more spread out, different sizes of these cells could be easily found in the sample.

Table 3: Unpaired T-test of the data

Null hypothesis: the size of Allium cepa cells equals to the size of Ovibos moschatus Oculi cells| Alternate hypothesis: the size of Allium cepa cells does not equal to the size of Ovibos moschatus Oculi cells| T-value: 15.4067| Degree of freedom: 28| Level of significance: 0.05| T-critical: 1.701131| The T-value is much greater than the T-critical; therefore the null hypothesis is rejected. |

*Error bars are based on the standard deviation calculated

*Error bars are based on the standard deviation calculated

Graph 1: Mean size of the Allium cepa and Ovibos moschatus Oculi cells

The unpaired T-test done calculated in table 3 and graph 1 further suggests that the sizes of the two types of cells are significantly different from each other as the null hypothesis was rejected and the error bars in the graph does not overlap. In graph one we could see that the size of Allium cepa cells are 267m larger than the Ovibos moschatus Oculi cells on average.

Conclusion

From all the calculations done in above, the sizes of Allium cepa cells are at least few times larger than the Ovibos moschatus Oculi cells. Allium cepa cells vary more in size in the cell samples since standard deviation was much higher (66.7m away from the mean size according to Table 2: Mean, median, mode and standard deviation of Allium cepa cells and Ovibos moschatus Oculi cells). The Ovibos moschatus Oculi cells had a more standardized size with less variation. The sizes of these two cells are significantly different from each other (null hypothesis was rejected in Table 3: Unpaired T-test of the raw data) this may due to the different...