Divide your data in half, your first 8 observations and your last 7 observations. Then use ANOVA to test to see if there is a significant difference between the two halves of your data. This list of Webpages that Perform Statistical Calculations has several ANOVA calculators.© BrainMass Inc. brainmass.com June 4, 2020, 3:30 am ad1c9bdddf
This solution is comprised of a detailed explanation to perform Analysis of Variance for one data set which is divided into two different subgroup as per the understanding of the data. Full description is given including, Null and Alternative Hypotheses, level of significance, ANOVA table, P-value, F-value, decision about rejecting or not rejecting the null hypothesis along with concluding remarks are given in the solution. ANOVA output is generated using excel add ins "Data Analysis".