Paragraph : The mean and standard deviation of 100 items are 50, 5 and that of 150 items are 40, 6 respectively. Question : What is the combined mean of all 250 items?

Step-by-step solution

Here, aligned & n₁=100, x ₁=50, ₁=5 & n₂=150, x ₂=40, ₂=6 & x ₁₂= 100 50+150 40 100+150 & = 5000+6000 250 = 11000 250 =44 aligned Hence, combined mean of all 250 items =44 .