Project and homework - Essay Example

> 30. Under the assumption that the population is distributed normally a two sample z test for independent samples with unknown σ1 and σ2 is suggested. The above mentioned test is used to test the difference between the means of two populations. The standardized test statistics is, The computed T-statistics and p-value with 5% level of significance and critical value t(0.05, 82) = 1.98, are exhibited in table 1.1. The computation is done under the assumption of unequal variances due to the observed difference of respective values in descriptive statistics (table 1.0) between both the samples. 2) Columns containing data are OLD, NEW.

This data contains information showing the amount of sales for 15 stores both before and after new shelf facings were installed. You suspect and wish to prove that the mean sales with the new facings is different from the mean sales under the old facings. The samples are considered as dependent due to the fact that they are related to same population. The population standard deviations of the both the samples are unknown. The sample sizes are considered to be small i.e. < 30. Under the assumption that the population is distributed normally a paired sample t-test is suggested.

The above mentioned test is used to test the difference between the means of two dependent samples. The standardized test statistics