Question

Determine the appropriate critical​ value(s) for each of the following tests concerning the population​ mean:

a.​ upper-tailed test:

alphaαequals=0.10

nequals=25

sigmaσequals=3.0

b.​ lower-tailed test:

alphaαequals=0.01

nequals=26

sequals=7.0

c.​ two-tailed test:

alphaαequals=0.02

nequals=51

sequals=5.9

d.​ two-tailed test:

alphaαequals=0.05

nequals=36

sigmaσequals=5.5

​(Round to two decimal places as needed. Use a comma to separate answers as​ needed.)

Answer 1

Solution :

a)

= 0.10

Z = Z _0.10 = 1.28

b)

sample size = n = 26

Degrees of freedom = df = n - 1 = 25

t _,df = -2.485

c)

sample size = n = 51

Degrees of freedom = df = n - 1 = 50

t _/2,df = + /- 2.403

d)

= 0.05

/ 2 = 0.05 / 2 = 0.025

Z_/2 = Z _0.025 = + /- 1.96