In a study about time motion, it was revealed that the time required by laborers to finished a specific manual activity was normally distributed with a mean of 26.6 minutes and a standard deviation of 3 minutes. A group of 25 laborers was randomly selected to get a special training for 2 weeks. After the training, it was revealed that their average time to complete the activity was 23 minutes. Can it be concluded that the activity is speed up by special training? Utilize a 0.05 level of significance. Also, include a graph showing the rejection and acceptance region.

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