MOI = 50.5 pfu / cell (A)		MOI = 5.05 pfu / cell (B)		MOI = 0.505 pfu / cell (C)		MOI = 0.051 pfu / cell (D)
Work station	Titre pfu / mL		Work station	Titre pfu / mL		Work station	Titre pfu / mL		Work station	Titre pfu / mL
1 (one)	9.15E+09		3	4.20E+08		5	5.10E+09		2	1.65E+08
1.04E+09		3.40E+07		5.15E+08		2.25E+08
4	3.20E+09		6	3.65E+08		7	8.10E+08		9	2.00E+08
8.05E+08				3.20E+07		1.36E+08
11	8.65E+10		8	1.10E+09		10	3.85E+08		12	1.14E+08
1.08E+09		6.80E+08		3.50E+08		1.22E+08
13	1.46E+09		15	1.10E+08		17	5.85E+08		14	1.54E+08
5.30E+09		8.55E+08		5.75E+08		2.44E+08
16	3.90E+09		18	2.85E+08		19	6.40E+08		21
4.90E+07		4.10E+08		3.50E+08
23	1.55E+09		20	6.50E+08		22	5.25E+08		24	1.50E+08
1.97E+09		1.15E+08		8.50E+08		6.15E+07
25	1.55E+09		27	3.75E+08		29	9.40E+08		26	1.24E+08
1.55E+09		6.60E+08		3.40E+09		2.05E+08
28	2.30E+09		30	5.45E+08		31	3.10E+08		33	1.42E+08
1.48E+10		3.80E+08		5.95E+07		6.35E+08
35	1.66E+09		32	1.80E+08		34	4.75E+08		36	1.75E+08
9.25E+08				2.13E+08		4.80E+08
38	7.90E+08		37	1.13E+09		39	2.21E+10		41	1.71E+06
1.11E+09		6.85E+08		1.07E+09		2.24E+08
43	5.70E+08		40	5.26E+08		42	3.15E+08		44	6.35E+08
1.12E+09		3.00E+08		2.65E+08		8.75E+08
46	2.10E+09		45	4.50E+08		47	3.80E+08		49	1.25E+08
		6.15E+08		9.90E+07		1.28E+08
A	5.40E+08		48	3.65E+08		50	1.28E+08		B	2.10E+08
1.11E+09		1.40E+08		2.40E+08		2.50E+08
E	6.25E+08		D	1.93E+08		C	2.50E+08		F	4.15E+08
1.05E+09		2.60E+08		4.20E+08		7.25E+07
I	3.60E+08		H	2.08E+08		G	6.56E+08		X	1.42E+08
1.62E+09		2.70E+08		5.00E+08

To see the trends of virus data more easily, virologists usually convert virus titres into log₁₀ values. By plotting mean log₁₀ (titre) vs. MOI, the y-axis is a linear scale, which helps in our interpretation of the overall results.

You will be expected to derive the standard deviation for each mean log₁₀ titre value, and these values should be used to plot error bars for evaluating the results. Take care here.

1. Using Excel, you cannot just accept its default settings for adding error bars - these will not work for your graph. add "Custom" error bars that correspond to the calculated standard deviation values.
2. Like the mean values that you are plotting on this graph, the standard deviation values need to be calculated from the log₁₀ values of the titres (not the actual titres).

Example:

If we recorded duplicate titres of 2.4 x 10⁸ pfu / mL and 3.6 x 10⁸ pfu / mL, these would convert to log₁₀ values of 8.38 and 8.56, respectively. Hence the log-scale graph would plot the mean of these duplicates, which is 8.47.

However, in our text, we would need to refer to the true mean titre, not the log value, so we would refer to the mean as 3.0 x 10⁸ pfu / mL

For our graph, we would likewise derive the standard deviation values from the log₁₀ values as well (here, it would be 0.12) - and use this value as our error bar for this mean. Search online for instructions for how Excel will add Custom error bars - it involves several steps, but it's quite straightforward once you have all your SD values, and in fact you add them all in one go.

• The titres that arise from each tested MOI must be analysed statistically in order for you to consider if there is a significant difference between the yield of virus when different MOIs are used.

Hi can you please explain this and what I am meant to do and how with the data represented in the table.If more information is required please let me know