Ch. 3. Inferential Statistics
I. Point Estimation: Using an unbiased statistic as the
estimation of a parameter.
II. Interval Estimation
A.
X
ยฑ cv(SE)
III. Hypothesis Testing
A. Definition: an inferential procedure to evaluate a
hypothesis by computing the probability associated
with a statistic through the sampling distribution of
the statistic.
B. Steps in Hypothesis Testing
1. Define two mutually exclusive hypotheses
a) Null Hypothesis (Ho): The hypothesis we do
not want to believe, which we want to
reject.
b) Alternative Hypothesis (H1): The hypothesis
we want to believe.
2. Define the decision rule about the probability of
the statistic (Called ฮฑ = .05 or .01) and obtain
the critical value of the ฮฑ (tcrit).
3. Compute the test statistic (tobs) from the sample
statistic
4. Make a decision by comparing tobs to tcrit.
If tobs
โฅ
tcrit, then reject Ho.
*Underlying logic: The farther we go away from the
mean, the larger the t-value, and the smaller the
probability cut off by the t-value.
C. Example
1. One-Sample z-test
2. One-Sample t-test
Docsity.com
