Researchers Wanted to Compare the Effectiveness of a Water Softener $\text { Group A (water softener and filtering) }$

Essay

Researchers wanted to compare the effectiveness of a water softener used with a filtering process with a water softener used without filtering.Ninety locations were randomly divided into two groups of equal size.Group A locations used a water softener and the filtering process,while group B used only the water softener.At the end of three months,the water was tested at each location for its level of softness.(Water softness was measured on a scale of 1 to 5,with 5 being the softest water.)The results were as follows. $\text { Group A (water softener and filtering) }$ mean = 2.1
standard deviation = 0.7 $\text { Group B (water softener only) }$ mean = 1.7
standard deviation = 0.4
Refer to the sample data to test whether there is a difference between the two types of treatments.Carry out the test with a 1% significance level.