University of the West of England

Twosample ttest (glass refractive index)
Link to Video Answer
In a forensic analysis, the refractive indices of two samples, A and B, of glass fragments are measured. Sample, A, collected from a broken window contains 7 fragments and the sample, B, from the clothing of a suspect contains 6 fragments. The last three digits in the measured values of their refractive indices are given below:
A 
214 
165 
159 
125 
162 
97 
182 
B 
348 
255 
244 
179 
250 
126 

Use Minitab to perform hypothesis tests to investigate whether there is any significant difference between the refractive indices of the two samples 
i) assuming that the samples are drawn from populations with equal variance,
ii) assuming that the samples are not drawn from populations with equal variance.