This guide explains a topic and a method for reading related news. It does not report a newly announced event. Check the issuing authority for current facts.
01 / UNDERSTANDING
Reading the news
For average-income or average-service-time coverage, ask how many observations each subgroup represents. A combined headline may change because group weights changed even when subgroup averages stayed constant.
02 / UNDERSTANDING
The concept in context
A weighted result must lie between the group averages when weights are positive. It is pulled closer to the average of the larger group. These bounds provide a quick reasonableness check, but they do not replace calculation when the exact value or an unknown group size is required.
03 / UNDERSTANDING
A worked learning case
Original educational case. Ten trainees average 60 points and twenty trainees average 75 points on an original diagnostic. Their totals are 600 and 1,500, giving 2,100 points across thirty trainees. The combined average is 70, not 67.5. The larger group has the higher average, so the combined result lies closer to 75.
ORIGINAL EDUCATIONAL PRACTICE
Try it before you check.
Original practice: Five values average 20 and fifteen values average 40. What is their combined average?
Show the answer and reasoning
35.
The first group totals 5 × 20 = 100 and the second totals 15 × 40 = 600. Their combined total of 700 is spread across twenty values, giving 35. It lies between 20 and 40 and closer to 40, which is sensible because that group is three times larger.
Two traps to watch for.
- Taking the simple mean of unequal-group averages.
- Adding averages without reconstructing the underlying totals.
YOUR TOPIC-SPECIFIC LEARNING MAP
Evidence to check
Convert each average back to a total.
Write the combined observation count.
Check the answer lies within the original range.
Explain the idea, apply it to a new situation, then check what changed in your reasoning.
BANKERS TUTORIAL · SOURCE NOTES
Keep the source alongside your notes.
Official links provide subject context and authoritative reference material. This guide’s explanation, scenario and question are original Bankers Tutorial learning content.
- sbi.bank.in https://sbi.bank.in/web/careers/current-openings
- sbi.bank.in https://sbi.bank.in/webfiles/uploads/files_2627/09/SBI_JA-Customer_Support_Sales-IH_Pre-2026-27_Eng.pdf
For SBI preparation, check the current official notice before relying on changing dates, rules or examination requirements.
