A randomized controlled trial is run to evaluate the effectiveness of a new drug for asthma in children. A total of 250 children are randomized to either the new drug or placebo . The mean age of children assigned to the new drug is 12.4 with a standard deviation of 3.6 years. The mean age of children assigned to the placebo is 13.0 with a standard deviation of 4.0 years. Is there a statistically significant difference in ages of children assigned to the treatments? Apply the two sample z test at a 5% level of significance.
1. Critical z value = +/-
2. Computed statistic=
3. Based on comparing the computed statistic to the critical value which of the following is true?
a. There is significant evidence, alpha=0.05, that there is a difference in ages of children assigned to the treatments.
b. There is not significant evidence, alpha=0.05, that there is a difference in ages of children assigned to the treatments.
c. Statistically speaking the difference in initial weights and weights after 6 weeks is 0.
d. b and c.