TWO- SAMPLE SIGN TEST

CASE ANALYSIS- 1

PROBLEM

The following data represents the amount of money spent per month by 15 housewives in Foreign Brand cosmetic items and Indian Brand cosmetic items.

Table-1: Sample Data

The hypotheses for the analysis are:

Null hypothesis-H0: The average amount spent on Foreign Brand cosmetic items and Indian Brand cosmetic items are equal.

Alternative Hypothesis- H1: The average amount spent on Foreign Brand cosmetic items and Indian Brand cosmetic items are not equal (Two tailed test)

Performing the Analysis with SPSS

For SPSS Version 11, click on Analyze ⇒ Non parametric tests ⇒ 2 Related Samples.  This will bring up the following SPSS screen dialogue box.

After clicking 2 Related Samples, this will bring up the following SPSS dialogue box.

Select the variables and move them to the Test Pair(s) list box and click Sign.

Finally click OK to get the output.

SPSS Output

The SPSS output are illustrated uin following tables.

Sign Test

Table-2: Test Statistics

a Binomial distribution used.

b  Sign Test

Table-3: Frequencies

a  Indian < Foreign

b  Indian > Foreign

c  Foreign = Indian

DECISION

Reject the null hypothesis if p-value (Sig. (2-tailed)) ≤ 0.05

INTERPRETATION

The p-value is 0.001 and it is less than 0.05 (5% level of significance), so we reject the null hypothesis and conclude that the average amount spent on Foreign Brand cosmetic items and Indian Brand cosmetic items are not equal.

SPSS Command

1. Click on ANALYZE at the SPSS menu bar (in older versions of SPSS, click on STATISTICS instead of ANALYZE.
2. Click on NON-PARAMETRIC TEST followed by 2 RELATED SAMPLES.
3. Select the concerned variables and move THEM TO TEST PAIR(S) LIST box.
4. Click SIGN.
5. Click OK of the main dialogue box.

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