Hypothesis Testing and Standard Normal Distribution

Assignment 2
PSYC 2525

a. Two tailed Z test
i. H0: ( μ=μ0 )
ii. H1: ( μ≠μ0 )
b. One Tailed Z Test
i. H0: ( μ≤μ0 ) or ( μ≥μ0 )
ii. H1: ( μ> μ0 ) (right tail) or ( μ< μ0 ) (left tail)
Standard Normal Table Used to Answer 2a, 2b, and 2c (Thomopoulos, Nick, 2018, p. 45-55).
a) Required area = P(0≤Z ≤2)= 0.47725
b) Required area = P( Z≤1)=P ( −∞< Z≤1 ) =0 .5+ P ( 0≤Z ≤1 ) = 0.5 + 0.341345 =
0.841345 = 0.84
c) P ( −∞< Z< α ) =0 . 95=0 . 5+0 . 45=0. 5+ P ( 0≤Z≤1 . 645 ) =P ( −∞< Z≤1 .645 ) , so required
Z-score = 1.645 below which 95% of the values will be positioned.
Decision you
make
Fail to reject the null
hypothesis (Accept) Reject the null hypothesis
True
nature of
the null
hypothesi
s
The null
hypothesis
is really true
Correct Conclusion Type –I error
The null
hypothesis
is really
false
Type –II error Correct Conclusion