APFIVE To study the effect of a new diet on blood pressure, a researcher compared a treatment group (n = 25) with a control group (n = 30). In analyzing the difference between the two independent sample means, the researcher used a pooled standard deviation. This approach requires the assumption that the population variances are equal, an assumption the researcher did not check. What statistical error was committed?
They inappropriately assumed equal variances for the two populations and used a pooled standard deviation without testing this assumption.
They mistakenly swapped the sample sizes when calculating the standard error.
They miscalculated the degrees of freedom by using an incorrect formula.
They incorrectly applied a one-sample t-test instead of a two-sample test.
Question Leaderboard
Not enough data yet to show leaderboard.