Some Useful Methods for Biostatistics
The first thing you can do with your data is something simple and somewhat useful: Find its center point. This is usually represented by two statistics: mean (average value) and median. The first is calculated in Excel with the function AVERAGE (see figure below).
The median is a bit more complicated, at least in real life, but in Excel it is just another simple function with the same name (see figure below).
Another useful statistical metric is standard deviation, which is a measure of dispersity. In other words, it shows how spread out your data are. It is calculated with a quite complicated formula, but in Excel it is just a simple function: STDEVA or STDEV (see figure below). STDEV assumes that your data are all the data available, while STDEVA assumes that you are using merely a sample of the available data.
To gain an insight on how the data are distributed, you can create a plot. Before doing that though, you will need to rearrange the data a bit--in this case sort them in ascending order (see figure below).
Afterwards, simply select all the data and click on the chart button. You may choose to tweak the chart next according to your preferences. In the end, it should look something like the one in the figure below.
What this plot shows is how the data are distributed. In this example, the plot's shape shows that the distribution is more or less linear.
A final method that is quite useful is that of the confidence interval. Given a confidence level (let's call it alpha) we can estimate an interval within the dataset's range where a data point is more likely to fall. The alpha is usually a small number (0.05 or 0.01) showing the chance of error (which is why it is set to be relatively small). If it was set to 0, the confidence interval would comprise the whole dataset. If it was set to 1, it would be reduced to a single point, the mean. You can find the confidence interval quite easily using the Excel formula CONFIDENCE (see figure below).
Once you calculate this, the confidence interval would be the range between (mean - confidence) and (mean + confidence). This becomes clearer in the figure below.