In: Statistics and Probability
Consider the following computer output:
Test of mu = 91 vs > 91
Variable | N | Mean | StDev | SE Mean |
x | 20 | 92.44 | 0.717 | 0.16 |
Find the 95% Lower bound.
SOLUTION:
From given data,
Null and Alternative hypothesis:
H0 = 91 vs Ha > 91
Find the 95% Lower bound.
Where,
sample = N = 20
sample mean = = 92.44
standard deviation = =0.717
Confidence interval is 95%
95% = 95/100 = 0.95
= 1 - Confidence interval = 1-0.95 = 0.05
/2 = 0.05 / 2
= 0.025
Z/2 = Z0.025 = 1.96
The Lower bound is
Lower bound = - Z/2 * ( / )
= 92.44 - 1.96 * (0.717 / √20 )
= 92.44 - 1.96 * (0.717 / 4.4721359)
= 92.44 - 1.96 * 0.160326
= 92.44 - 0.31423896
= 92.1257
The 95% Lower bound is 92.1257