When a poultry farmer uses her regular feed, the chickens attain normally distributed weights with a mean of 1.77kg. In an experiment with an enriched feed mixture, nine chickens are born that attain the weights given below:

1.74 1.77 1.90 1.80 1.88 1.87 1.79 1.81 1.89

Use 0.01 level of significance to test the claim that the mean weight is higher with the enriched feed.