Statistics View

The temperature data in a Temprecord data window can be displayed in one of four view modes. These are summary view, statistics view, values view and graph view. The statistics view displays an analysis of the temperature data in relation to the display lower and upper limits, and the start and end samples. You need to read the logged temperature data to see the statistics view of the logger. Using the File/Query Logger function only reads the summary data.

You can select the statistics view mode by opening the View menu and clicking on 'Statistics'.

When the logger is recording temperatures outside its logging range, the temperature actually recorded will be limited to the minimum or maximum temperature specified, and in the case of the Mon-T logger the temperature will be limited to the values specified or displayed on the Mon-T parameters. This has implications for calculated statistics, as the values used in the calculations do not reflect the actual temperatures the logger was subjected to.

Take care when interpreting statistics from Mon-T loggers that have exceeded the programmed Minimum or Maximum temperature range, and in general when interpreting temperatures outside the specifications of the logger

•the number and percentage of samples that were above the display upper limit.

•the number and percentage of samples that were below the display lower limit.

•the number and percentage of samples that were both above the display upper limit and below the display lower limit.

If Humidity was logged instead, these statistics are available for the logged humidity samples. If both Humidity and Temperature were logged, these statistics are available for both. You can select between them by using the View/Temperature, View/Humidity, and View/Temperature and Humidity menu options.

The general statistical information is presented for up to three separate groups - all samples, samples between start and end markers, and samples in the visible graph window.

The statistical information is presented for all samples in the logger. This group is always presented in the statistics view on screen and in the printed report, if the Show General Statistics option is checked.

If you have set start and end samples that are different from the first and last samples in the logger, the above parameters are calculated again using only those samples between the start and end samples. The statistical information is then presented for those samples. This group also is presented in the printed report, if the Show General Statistics option is checked.

This is useful when you want to exclude a portion of the data record, e.g. the time when the logger was not in a controlled environment.

If you have the graph view of the logger samples displayed, and the displayed range is not the entire sample record, and the displayed range is different to the range between the start and end markers, then the above parameters are calculated again using only those samples that are visible on the graph view window. The statistical information is then presented for those samples. This group also is presented in the printed report, if the Show General Statistics option is checked.

Note that although this statistics option is called "Samples Visible in the Graph View", what we really mean is "samples present in the date range currently displayed in the graph view". This can affect the statistics in the following manner:

•the mean and standard deviation statistics may be calculated including samples that you can't currently see in the graph view.

•the maximum and/or minimum samples could be off-screen.

The averaging functions built into Temprecord exporting make it relatively easy to generate a report of daily temperature averages. See Exporting daily average temperatures for more information.

Temprecord can also calculate and display TTV (Total Temperature Value) statistics. To enable this facility, click on Options/Statistics, and make sure Show TTV Statistics is checked. The TTV statistics are displayed after the statistics for all samples and statistics for samples between the start and samples are displayed. The TTV statistics are calculated for one or more periods starting from the start sample. The temperature limits, duration and number of TTV periods are set using the statistics view options

For more information on the derivation and application of TTV statistics, see the topic Total Temperature Value. There are also options that control whether the TTV statistical data is shown, printed or exported. See Graph View Options, Printing Options, and Export Options for more details.

Temprecord can also calculate and display PHI (Process Hygiene Index) statistics. To enable this facility, click on Options/Statistics, and make sure Show Growth Statistics is checked. The PHI statistics are displayed after the statistics for all samples and statistics for samples between the start and samples are displayed. The PHI statistics are calculated between the start and end samples only.

The PHI statistics are presented as a guide only. They do not represent any actual measured growth of organisms present in the monitored environment. The statistics calculated are based on information and techniques developed by the Meat Research Institute of New Zealand.

For more information on the derivation and application of PHI statistics, see the topic Process Hygiene Index.

Mean Kinetic Temperature (MKT) is a way of expressing the overall effect of temperature fluctuations during storage or transit of perishable goods with a single temperature value, the Mean Kinetic Temperature.

MKT is a calculated, single temperature that is better represents the effects of temperature variations over a period of time then a simple averaging of the temperatures.

Temprecord calculates the MKT value for the samples between the start and end samples and displays the value on the graph view and Statistics view.

Temprecord can also calculate and display RI (Refrigeration Index) statistics. To enable this facility, click on Options/Statistics, and make sure Show Refrigeration Index Statistics is checked. The RI statistics are displayed after the PHI statistics. The RI statistics are calculated between the start and end samples only. Remember that if a file has just been loaded the start sample is set to the first sample and the end sample to the last sample.

The RI value is calculated for each sample and is cumulative. If the temperature falls below 7.0 degrees C the RI value at this point is reported. The RI value is also reported at the end sample, regardless of whether the 7.0 degree C temperature was reached.

The time interval taken for the temperature to fall to 7.0 degrees C is also reported.

The RI value displayed is a logarithmic value, and represents the base 10 log of the number of generation increases over the time period.

The RI statistics are presented as a guide only. They do not represent any actual measured growth of organisms present in the monitored environment. The statistics calculated are based on information and techniques developed by Meat and Livestock Australia.

For more information on the derivation and application of RI statistics, see the topic Refrigeration Index.

You can also change the view mode from the pop-up menu that displays when you press the right-hand mouse button.