Marine biologists investigated the effect of microplastic exposure on the metabolic activity of juvenile shore crabs (Carcinus maenas).

The oxygen consumption rates of $15$ juvenile crabs incubated in pristine, filtered seawater were measured ( $n_1 = 15$ ). A second group of $15$ juvenile crabs was incubated in seawater contaminated with polystyrene microplastics ( $n_2 = 15$ ).

The mean oxygen consumption rates (in $g−1h−1\mu\text{mol O}_2\text{ g}^{-1}\text{h}^{-1}$ ) and standard deviations for the two groups were recorded:

Control (pristine seawater): $32.4 \pm 2.8$
Exposed (microplastics): $24.1 \pm 3.1$

Identify the appropriate statistical test to compare the means of these two independent groups, and calculate the degrees of freedom ( $df\text{df}$ ) for this test.

The statistical test was performed, yielding a $p$ -value of $p < 0.001$ . Using the words probability, chance, and significant, draw a scientific conclusion from this result.

Marine biologists investigated the effect of microplastic exposure on the metabolic activity of juvenile shore crabs (Carcinus maenas).

The mean oxygen consumption rates (in $g−1h−1\mu\text{mol O}_2\text{ g}^{-1}\text{h}^{-1}$ ) and standard deviations for the two groups were recorded:

Control (pristine seawater): $32.4 \pm 2.8$
Exposed (microplastics): $24.1 \pm 3.1$

Identify the appropriate statistical test to compare the means of these two independent groups, and calculate the degrees of freedom ( $df\text{df}$ ) for this test.

The statistical test was performed, yielding a $p$ -value of $p < 0.001$ . Using the words probability, chance, and significant, draw a scientific conclusion from this result.

Analysis

Question 15

Markscheme

Analysis

Question 15

Markscheme

Analysis

Question 15

Analysis Questions

Analysis

Question 15

Analysis Questions