Fifty Points in Five Branches

Difficulty: Medium · Topics: Probability, Statistics, z-Scores

The table shows the mean and standard deviation of an exam taken in five branches of a bank.

Branch A B C D E --- --- --- --- --- --- Mean 40 45 65 70 60 Std. dev. 6 1 3 20 3

In which branch would a score of 50 count as most successful, and in which as least successful?

(The z-score of a value x is z=(x-bar x)/(s), where bar x is the mean and s the standard deviation.)