Answer:
Option a
Step-by-step explanation:
Given two normal distribution samples
I group has 106 as mean and 8.5 as std deviation with sample size = 60
II group has 121 as mean and 6.3 as std deviation with sample size =38
We find mean difference =-15
For margin of error finding, we have to find the combined std error for the difference
Variance of difference = Sum of variances
STd error for difference = 1.50
Hence for 99% margin of error =2.58(1.50)
= 3.87
well, a right-triangle will have one angle that is 90°, and using the pythagorean theorem, we also know that the longest side is really the root of the sum of the square of the other two. After all that mouthfull let's check