The 68-95-99.7 % rule is an approximation. It says that 95% of the data in a bell curve is contained within two standard deviations either side of the mean. What is the exact value (of z from the normal table) that contains 95% of the data.

Select one or more:

a.1.645

b.2.33

c.2.575

d.3.5

e.1.96