What is the Critical z value and Computed statistic? Apply the two sample z test at a 5% level of significance.
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 (125 per group). 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 points)
2. Computed statistic= (2 points)
3. Based on comparing the computed statistic to the critical value which of the following
is (are) true? (6 points)
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.