wo manufacturing companies of soap each claims that their product is superior in whitening one’s complexion. A researcher did an experiment by randomly choosing two groups and assigning each group to use the product for one month. Results are shown below where the higher the number, the more effective the product in skin whitening. At  (t-tabular value is ) level, is there a significant difference between the two products effectiveness in skin whitening?

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Types of Bias

Statistics is the study of data collection, organization, analysis, interpretation, and presentation. Statistical bias is a characteristic of a statistical technique or its findings in which the expected value deviates from the actual root quantitative parameter being estimated. According to the actual definition of bias, it refers to the tendency of a statistic to overestimate or underestimate a parameter.