Average after dropping a subgroup

EasyStatistics~3m

A book of 5050 positions returns 8%8\% on average this quarter. You cut the 1010 worst positions, which averaged −12%-12\%. What is the average return of the 4040 positions you kept? Give a percent to one decimal.

Show hints (2)+
  1. Work in totals: whole book =50×8=400=50\times8=400; dropped =10×(−12)=10\times(-12).
  2. Kept total =400−(−120)=400-(-120), then divide by the remaining 4040 positions.

Answer

Reveal answer →

13 (± 0.001)

Create a free account to see the full worked solution and track your progress.

Interview format: Trading Aptitude Tests, Betting Game Rounds

Related questions