> For the complete documentation index, see [llms.txt](https://help.sbtinstruments.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.sbtinstruments.com/tutorials/measure-vitroid-tm-growth-curve/data-analysis.md).

# Data analysis

Once the measurements have been completed, it is time to analyze the data. The following section explains how to plot the growth curve and determine the generation time.

We have included one of our own growth experiments as an Excel template.

{% file src="/files/XfY4WYnohyOmtMfOGR11" %}

{% hint style="info" icon="laptop-mobile" %}

## Plot data with ease in Access

To keep things simple, this tutorial demonstrates how to use BactoBox® as a stand-alone device.

Once you are familiar with the fundamentals, we recommend connecting BactoBox® to a computer and running the measurements through BactoBox® Access. This makes it easy to record sampling times and dilution factors and provides a real-time plot of your data.

See [Track growth curve](/mpd/mini-course/track-growth-curve.md) for a mini-course on tracking a growth curve using BactoBox® Access.
{% endhint %}

## Step by step

{% stepper %}
{% step %}

### Transfer your data to the template

Manually replace the data in the excel template with your data.

Remove any data old data entries that do not belong to your data
{% endstep %}

{% step %}

### Add information on inoculation time

Cell B14 is used for automatic calculation of incubation time. Update the cell with time stamp from your incubation time.
{% endstep %}

{% step %}

### Plot the data

The x/y plot in the template will automatically plot the data on a log-10 y-axis.

The below plot is from our run of the tutorial.

* The solid data points are used to generate an exponential fit.
* The hollow data points are excluded from the fit since they are already in deceleration/stationary stage.

<figure><img src="/files/zDhgakSGzJHSww6zkMBU" alt=""><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### Identify the data belonging to exponential growth stage

Click one of the solid data points and use the mouse to select the x/y range where the data are on a straight line, i.e. the exponential growth stage. In this tutorial it will typically be from \~1×10<sup>7</sup> up to \~1×10<sup>9</sup> cells/mL.

If the exponential model provides a good fit to your data the R<sup>2</sup> should be close to 1.

<figure><img src="/files/CMAmK8j4zfNZyFajFb0e" alt="" width="375"><figcaption></figcaption></figure>
{% endstep %}

{% step %}

### Determine growth rate

The <mark style="background-color:$success;">green</mark> number on the plot is the growth rate per hour calculated via the exponential fit.
{% endstep %}

{% step %}

### Calculate generation time

Change the number in cell B27 to the green number from your dataset.

This will automatically calculate the generation time in hours (cell C28) and minutes (cell C29). The SBT data set resulted in a growth rate of 1.72 h<sup>-1</sup> and a generation time of 24.2 min.

<figure><img src="/files/zlRYb18Ue4OmJbujQJGs" alt="" width="218"><figcaption></figcaption></figure>
{% endstep %}
{% endstepper %}

## Summary

Here we detailed how to plot data and calculate growth rates and generation times. To keep things simple, we used manual data entry in a classic Excel template.

On the next page, [Summary](/tutorials/measure-vitroid-tm-growth-curve/summary.md), we will recap the tutorial and provide inspiration for the next steps in your BactoBox® journey.


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