Answer:
Given,
Here at 90% CI, z value is 1.645
a)
sample n = 100, xbar = 102.2 , s = 2.28
90% CI = xbar +/- z*s/sqrt(n)
substitute values
= 102.2 +/- 1.645*2.28/sqrt(100)
= 102.2 +/- 0.3751
= (101.825 , 102.575)
b)
sample n = 90, xbar = 84.8, s = 2.19
90% CI = xbar +/- z*s/sqrt(n)
substitute values
= 184.8 +/- 1.645*2.19/sqrt(90)
= 184.8 +/- 0.3797
= (184.420 , 185.180)
c)
sample n = 80, xbar = 55.8, s = 2.48
90% CI = xbar +/- z*s/sqrt(n)
substitute values
= 55.8 +/- 1.645*2.48/sqrt(80)
= 55.8 +/- 0.456
= (55.344 , 56.256)
d)
sample n = 90, xbar = 76.3, s = 2.68
90% CI = xbar +/- z*s/sqrt(n)
substitute values
= 76.3 +/- 1.645*2.68/sqrt(90)
= 76.3 +/- 0.465
= (75.835 , 76.765)
(1 point) A random sample of n measurements was selected from a population with unknown mean...
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