Question

Using the unit normal table, find the proportion under the standard normal curve that lies between the following values. (Round your answers to four decimal places.) (a) the mean and z = 0 0.3989 Incorrect: Your answer is incorrect. (b) the mean and z = 1.96 0.0250 Incorrect: Your answer is incorrect. (c) z = −1.30 and z = 1.30 (d) z = −0.80 and z = −0.20

Answer 1

a) For standard normal variable mean is zero and variance is 0,

So the proportion is 0

b) As the mean is equal to zero and from normal table we have

and

Hence the required proportion is

c) We know from normal table that

Hence the proportion is

d) Normal table gives

and  

Hence