Page 63 - Quantitative Data Analysis

Quantitative Data Analysis
Simply Explained Using SPSS

Two sample independent t-test is used when a researcher is
interested to test the mean significance difference between two
groups.
Question(s) answered

1. Is one group mean statistically different from, greater than,
or less than another group mean, when the two groups are
independent from one another?
Example Case for independent t-test

A researcher believes students learn statistics better if taught using
graphics rather than equations. To evaluate her hypothesis, she
recruits 20 students from an introductory education course and
randomly assigns them to two groups.

Hypotheses for an Independent Sample t-test

• The null hypothesis still represents no difference.

H 0 :μ 1 = μ 2
• The alternative hypothesis is the hypothesis where there is a
difference.

H 1 :μ 1<μ 2
H 1 :μ 1 = μ 2 or H 1 :μ 1>μ 2 or
• Alternatively can represent as mean differences:
H 0: μ 1 −μ 2 = 0

H 1: μ 1 − μ 2 = 0; or H 1: μ 1 − μ 2> 0; or H 1: μ 1 − μ 2< 0.

The Theory and Applications of Statistical Inferences 47