2. Sampling Distribution
Representation of the sample statistic
values obtained from every conceivable
sample of a certain size chosen from a
population by using a specified
sampling procedure along with the
relative frequency of occurrence of
those statistic values
8. Central Limit Theorem
When the sample size is sufficiently large, the
sampling distribution associated with the sampling
procedure display the properties of a normal
distribution.
10. Given n = 100, x = 1,278 units, and s = 399
units
To Construct 95 percent confidence interval
s 399
sx = --- = ----- = 39.9 units
n 100
The 95 percent confidence interval is
x ± 1.96 *sx = 1,278 ± (1.96)(39.9) =
1,278 ± 78.204 = 1,278 ± 78, approximately
Confidence Estimation for
Interval Data (Cont’d)
11. Confidence Estimation for
Interval Data (Cont’d)
Interpretation
From the sample data, we can be 95
percent confident that the average annual
sales of men's suits, across all men's
clothing stores in the population, are
between 1,200 and 1,356 units