Question

An Analyst wants to know if there was a significance difference in the average of hours worked in a week from 2000 (Group 1) to 2004 (Group 2). He gathers all the data from the General Social Survey, and lists the following summary statistics from the sampling.

Year	2000	2004
Mean	27.34	48.12
Std. Dev	10.11	19.23
Unweighted n	43	54

Source: General Social Survey (sda.berkeley.edu )

What is the correct null hypothesis?

Ho: mu2004-mu2000 < 0

Ho: mu2004-mu2000 does not equal 0

Ho: mu2000-mu2004 > 0

Ho: mu2004-mu2000 = 0

Answer 1

Solution:

Null and alternative hypothesis are :

Ho:

Ha:

This corresponds to a two-tailed test, for which a t-test for two population means, with two independent samples, with unknown population standard deviations will be used.

We don't know about variances are equal or not.

We have to find P-value, using excel =TDIST(6.842,83.486,2)

Using the P-value approach: The p-value is p = 0, and since p=0<0.05, it is concluded that the null hypothesis is rejected.

Conclusion: It is concluded that the null hypothesis Ho is rejected. Hence, there is a significance difference in the average of hours worked in a week from 2000 (Group 1) to 2004 (Group 2)

Done