Hypothesis test for single mean.

Experience raising New Jersey Red chickens revealed the mean weight of the chickens at five months is 4.35 pounds. The weights follow the normal distribution. In an effort to increase their weight, a special additive is added to the chicken feed. The subsequent weights of a sample of five month old chickens were (in pounds) as shown:
4.41, 4.37, 4.33, 4.35, 4.30, 4.39, 4.36, 4.38, 4.40, 4.39.
1. Establish the null hypothesis (H0) and the alternate hypothesis (Ha).
2. Indicate the level of significance, and determine critical value, tCR.
3. Divide the test statistic (t) 
4. Formulate a decision rule based on steps a, b & c above.
5. Create a decision regarding the null hypothesis based on the sample information. Interpret the results of the test and state your conclusion.