Algebra homework

Question

A shipment of beach balls with a mean diameter of 28cm and a standard deviation of 1.3cm is normally distributed. By how many standard deviations does a ball beating with a diameter of 26.7cm differ from mean?

A. 1.3

B. 3

C. 2

D. 1

Answer 1

the z-score is (28 - 26.7)/1.3 = 1.3/1.3 = 1

option D please