Lula-Rae inc, claims that ingesting a concoction of lemon and lavender essential oils will significantly elevate mood in consumers. To test this, a skeptical premedical student selects a sample of 81 participants. Each participant drinks a mi of the essential oils and then completes a mood inventory. The population score on this mood inventory has a mean=30 with a standard deviation =5. The sample of n=81 participants had a mean score of M=41. Calculate the z observed value that would result from this hypothesis test. (be sure to round your answer to the second decimal

place.)