The table below presents a summary of the possible t-test outcomes.
|Interpretation of the t-test stars () for hybrid side-by-side yield comparisons.|
INTERPRETATION OF PAIRED COMPARISONSWhere stars are shown below each comparison, this indicates the level of confidence that a real yield difference actually exists between the two hybrids based on the yield data. Yield superiority can only be concluded where one to three stars are present.
|P VALUE||CONFIDENCE LEVEL||SCIENTIFIC DESIGNATION||LEVEL OF SIGNIFICANCE||YIELD ADVANTAGE||INTERPRETATION|
|<0.001||>99.9%||Very highly significant||YES||Product superiority for yield is shown. Can confidently plant a product providing no key agronomic traits are limiting, and/or if a key trait advantage exists. Check the trait ratings for any considerations.|
|<0.10||>90.0%||CA||Commercially Acceptable||YES||Not a significant result, but may be regarded as commercially acceptable from which to base a decision.|
|<0.10||>90.0%||Not significant||NO||Product superiority for yield cannot be claimed. Ignore the yield comparison and refer primarily to trait ratings to select between the products.|
“The more stars () present for the comparison, the more confident we can be that the measured average side-by-side yield difference is due to an actual genetic yield difference between the two hybrids rather than just chance.”
Where a result is commercially acceptable (CA), the result is not designated as statistically significant, but it may be regarded as commercially acceptable. Where a result is not significant, we cannot conclude there is a yield difference between the hybrids. This may have two principle implications:
On the other hand, yields may appear to be very similar but still achieve significance - this happens in cases where yield variations are small and the number of trial locations is large.
A t-test analysis of statistical significance is now carried out on all Pioneer side-by-side comparisons and we take great care to base our product yield statements on the outcome.
Hybrid summaries in this publication use the following equations to calculate milk profit ($/ha), for silage harvested in 2016.
* For more details on the cost of production for 2021/2022 click here