Statistical Assumption of the independent sample t test:

1. The data should be collected by random sampling.

2. The sample should be independent from each other.

3. The data should be continuous or we can say that the data should be either interval level or ratio level for t test.

Using the data set you have selected, select independent and dependent variables.

Here we have

Independent Variable: Productivity Drive during 2009 and 2010

Dependent Variable: Daily Revenue per Square Foot

Develop the null and the alternative hypothesis.

Null Hypothesis (Ho): There is no significant difference in the mean Daily Revenue per Square Foot in 2009 and 2010.

Alternative Hypothesis (Ha): There is a significant difference of mean Daily Revenue per Square Foot has improved in 2010 as compare to 2009.

Mathematically;

Null Hypothesis (Ho): µ1 = µ2

Alternative Hypothesis (Ha): µ1 ≠ µ2

Where µ1 = Mean of the married women who wants abortion for any reason.

µ2 = Mean of the unmarried women who wants abortion for any reason.

Level of Significance = .05

The below syntax is used to calculate the Independent sample t test for the above mentioned data.

GET

FILE='C:\Users\rajan\Desktop\cof1stat7644due11_00pm06022011\gss04student-week 8.sav'.

DATASET NAME DataSet1 WINDOW=FRONT.

GET

FILE='C:\Users\rajan\Desktop\cof1stat7644due11_00pm06022011\gss04worth-week 8 ptll.sav'.

DATASET NAME DataSet2 WINDOW=FRONT.

DATASET ACTIVATE DataSet1.

T-TEST GROUPS=ABANY(1 2)

/MISSING=ANALYSIS

/VARIABLES=MARITAL

/CRITERIA=CI(.95).

Use the SPSS to calculate an independent-samples t test.

Group Statistics
ABORTION IF WOMAN WANTS FOR ANY REASON / N / Mean / Std. Deviation / Std. Error Mean
MARITAL STATUS / dimension1 / YES / 197 / 2.59 / 1.717 / .122
NO / 275 / 2.24 / 1.590 / .096
Independent Samples Test
Levene's Test for Equality of Variances / t-test for Equality of Means
F / Sig. / t / df / Sig. (2-tailed) / Mean Difference / Std. Error Difference / 95% Confidence Interval of the Difference
Lower / Upper
MARITAL STATUS / Equal variances assumed / 6.100 / .014 / 2.249 / 470 / .025 / .345 / .153 / .044 / .647
Equal variances not assumed / 2.221 / 402.227 / .027 / .345 / .155 / .040 / .651

Report on the p value and the confidence interval.

Here we have p values are .025 and .027 for equal variance assumed and equal variances not assumed respectively. Confidence Interval are (.044, .647) and (.040, .651) for equal variance assumed and equal variances not assumed respectively.

Interpret the confidence interval.

Here we can say that by seeing the confidence interval the mean difference lies between .044 and .647 for equal variance assumed and for equal variance not assumed, the mean difference lies between .040 and .651. We are 95% confident that the mean difference lies between these two values known as lower and upper confidence values.

Decide whether to reject or retain the null hypothesis.

Since here P-values for equal as well as unequal variances are less than the level of confidence. The p-values are .025 and .027 for equal and unequal variance respectively, which is less than .05. So we will reject the null hypothesis in this case. So we can conclude that there is a significant difference of mean marital status among these two groups that are abortion or no abortion.