a total of 250 children are randomized either to the new drug or the placebo 125 per group The mean age of the children assigned to the new drug is 12.4 with a standard deviation of 3.6 years. The mean age of the children assigned to the placebo is 13.0 with a standard deviation of 4.0 years. is there statistical difference in ages of children assigned to the treatments apply the two sample z test at 5% level of signifciance

Critical z value=+/-

computed statistic