Question

Help me with the following problem :(
Problem
If a set of observations are normally distributed, what percentage of these differs from the mean by:
a) more than 1.3 ??
b) less than 0.52 ??

Answer 1

Solution :

Using standard normal table,

(a)

1 - P(-1.3 < z < 1.3)

= 1 - [P(z < 1.3) - P(z < -1.3)]

= 0.1936

19.36%

(b)

P(-0.52 < z < 0.52)

= P(z < 0.52) - P( z < -0.52)

= 0.3969

39.69%