Methods and apparatus for determining whether a media presentation device is in an on state or an off state are disclosed. A disclosed example method comprises determining contribution values from at least one of a signal measured from a sensing device or an output signal accessed from the presentation device, wherein the contribution values are indicative of a state of a presentation device. Summing, via a logic circuit, a first plurality of the contribution values corresponding to a first measurement cycle to generate a first intermediate fuzzy score for the first measurement cycle. Storing the first intermediate fuzzy score in a buffer including a plurality of intermediate fuzzy scores corresponding to respective measurement cycles. Combining, via the logic circuit, the intermediate fuzzy scores corresponding to a first time period to form a final fuzzy score. When the final fuzzy score satisfies a threshold, setting the state of the presentation device as on and enabling crediting of media presented by the presentation device.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method to determine a state of a presentation device, comprising: determining contribution values from at least one of a signal measured from a sensing device or an output signal accessed from the presentation device, wherein the contribution values are indicative of a state of a presentation device; summing, via a logic circuit, a first plurality of the contribution values corresponding to a first measurement cycle to generate a first intermediate fuzzy score for the first measurement cycle; storing the first intermediate fuzzy score in a buffer including a plurality of intermediate fuzzy scores corresponding to respective measurement cycles; combining, via the logic circuit, the intermediate fuzzy scores corresponding to a first time period to form a final fuzzy score; when the final fuzzy score satisfies a first threshold, setting the state of the presentation device as on and enabling crediting of media presented by the presentation device. 2. The method as defined in claim 1, wherein the combining of the intermediate fuzzy scores includes averaging the intermediate fuzzy scores corresponding to the first time period. 3. The method as defined in claim 1, further including removing outliers from the buffer before combining the intermediate fuzzy scores to form the final fuzzy score. 4. The method as defined in claim 3, wherein the removing of the outliers includes removing ones of the intermediate fuzzy scores that fall outside a range based on one or more percentiles. 5. The method as defined in claim 1, wherein the final fuzzy score is one of a set of final fuzzy scores, and further including calculating a minimum final fuzzy score and a maximum final fuzzy score in the set of final fuzzy scores. 6. The method as defined in claim 5, further including comparing a difference between the minimum final fuzzy score and the maximum final fuzzy score to a second threshold. 7. The method as defined in claim 6, further including applying a normalization factor to respective ones of the final fuzzy scores of the set when the difference is greater than the second threshold. 8. The method as defined in claim 1, wherein the buffer is a circular buffer. 9. A tangible machine readable storage medium comprising instructions that, when executed, cause a machine to at least: determine contribution values from at least one of a signal measured from a sensing device or an output signal accessed from the presentation device, wherein the contribution values are indicative of a state of a presentation device; sum a first plurality of the contribution values corresponding to a first measurement cycle to generate a first intermediate fuzzy score for the first measurement cycle; store the first intermediate fuzzy score in a buffer including a plurality of intermediate fuzzy scores corresponding to respective measurement cycles; combine the intermediate fuzzy scores corresponding to a first time period to form a final fuzzy score; and when the final fuzzy score satisfies a first threshold, setting the state of the presentation device as on and enabling crediting of media presented by the presentation device. 10. The tangible machine readable medium as defined in claim 9, wherein the instructions cause the machine to combine the intermediate fuzzy scores by averaging the intermediate fuzzy scores corresponding to the first time period. 11. The tangible machine readable medium as defined in claim 9, wherein the instructions cause the machine to remove outliers from the buffer before combining the intermediate fuzzy scores to form the final fuzzy score. 12. The tangible machine readable medium as defined in claim 11, wherein the instructions cause the machine to remove the outliers by removing ones of the intermediate fuzzy scores that fall outside a range based on one or more percentiles. 13. The tangible machine readable medium as defined in claim 9, wherein the final fuzzy score is one of a set of final fuzzy scores, and the instructions cause the machine to calculate a minimum final fuzzy score and a maximum final fuzzy score in the set of final fuzzy scores and to compare a difference between the minimum final fuzzy score and the maximum final fuzzy score to a second threshold. 14. The tangible machine readable medium as defined in claim 13, wherein the instructions cause the machine to apply a normalization factor to respective ones of the final fuzzy scores of the set when the difference is greater than the second threshold. 15. The tangible machine readable medium as defined in claim 9, wherein the buffer is a circular buffer. 16. An apparatus to determine a state of a presentation device, comprising: an analyzer to determine contribution values from at least one of a signal measured from a sensing device or an output signal accessed from the presentation device, wherein the contribution values are indicative of a state of a presentation device; the analyzer to sum a first plurality of the contribution values corresponding to a first measurement cycle to generate a first intermediate fuzzy score for the first measurement cycle; a buffer to store the first intermediate fuzzy score, the buffer including a plurality of intermediate fuzzy scores corresponding to respective measurement cycles, the analyzer to combine the intermediate fuzzy scores for a first time period to form a final fuzzy score; and a creditor to set the state of the presentation device as on and enable crediting of media presented by the presentation device when the final fuzzy score satisfies a first threshold, at least one of the analyzer, the buffer or the creditor including hardware. 17. The apparatus as defined in claim 16, wherein the analyzer is to combine the intermediate fuzzy scores by averaging the intermediate fuzzy scores corresponding to the first time period. 18. The apparatus as defined in claim 16, wherein the analyzer is to remove outliers from the buffer, by removing ones of the intermediate fuzzy scores that fall outside a range based on one or more percentiles, before combining the intermediate fuzzy scores to form the final fuzzy score. 19. The apparatus as defined in claim 16, wherein the final fuzzy score is one of a set of final fuzzy scores, and the analyzer is to calculate a minimum final fuzzy score and a maximum final fuzzy score of the set of final fuzzy scores and compare a difference between the minimum final fuzzy score and the maximum final fuzzy score to a second threshold. 20. The apparatus as defined in claim 19, wherein the analyzer is to apply a normalization factor to respective ones of the final fuzzy scores of the set when the difference is greater than the second threshold.