Question: Convicted murderers receive a sentence of an average of 18.7 years in prison. A criminologist wants to perform a hypothesis test to determine whether the mean sentence by one particular judge differs from 18.7 years. A random sample of 40 cases from the court files from this judge is taken. It is found that sample mean is 17.2 years. Assume that the population standard deviation is 7.4 years. Test at the 0.05 significance level.
[A] Use the critical value z0 method from the normal distribution.
1. H0:
Ha:
2. α =
3. Test statistics:
4. P-value or critical z0 or t0.
5. Rejection Region:
6. Decision:
7. Interpretation:
[B] Use the P-value method.
1. H0:
Ha:
2. α =
3. Test statistics:
P-value or critical z0 or t0
4. Rejection Region:
5. Decision:
6. Interruptions: