Scottish Highers Human Biology Experimental Design: A protein supplement is used by

Question

A protein supplement is used by some people who take part in sport. They believe its use increases muscle mass and therefore improves performance in sporting activities such as weightlifting.

An investigation was carried out to test if protein supplements improved the ability of the upper leg muscles to raise weights.

A class of 20 students was divided into two groups, A and B. The groups were balanced for age, gender, fitness level and body mass.

Each student carried out 10 weeks of regular training on the apparatus.

Students in group A took a daily dose of a protein supplement.

Students in group B took a daily dose of a placebo.

All students had their results recorded every 2 weeks for 10 weeks, by measuring the maximum weight that could be raised using the apparatus shown in the diagram.

(a) State two additional variables, other than those described above, that would need to be controlled during this investigation.
1 ________________
2 ________________

(b) The results from the investigation are shown in Table 1.

Table 1
Average maximum weight raised (kg)
Time (weeks)       0   2   4   6   8   10
Group
A (protein supplement)    52  57  64  72  86  95
B (placebo)                50  55  60  68  74  80

(i) Draw a line graph to show all the data in Table 1.
(Additional graph paper, if required, can be found on page 30)

(ii) State the conclusion that can be drawn from these results.

__________________________________________________________

(iii) Suggest a reason for the increase in performance of Group B.

__________________________________________________________

(c) The average body mass and percentage body fat of the students was measured at the start of the investigation and after 10 weeks.

The measurements for each group are shown in Table 2.

Table 2
Group       Measurement        Start (0 weeks)      After 10 weeks
A (protein supplement)     body mass (kg)     60.7                  62.5
                               body fat (%)            28.3                  23.8
B (placebo)                 body mass (kg)     60.5                  61.3
                               body fat (%)            27.9                  25.8

Use the data to explain why taking protein supplements resulted in a greater increase in muscle mass.
__________________________________________________________

A protein supplement is used by some people who take part in sport - Scottish Highers Human Biology - Question 4 - 2019

Worked Solution & Example Answer:A protein supplement is used by some people who take part in sport - Scottish Highers Human Biology - Question 4 - 2019

State two additional variables, other than those described above, that would need to be controlled during this investigation.

Draw a line graph to show all the data in Table 1.

State the conclusion that can be drawn from these results.

Suggest a reason for the increase in performance of Group B.

Use the data to explain why taking protein supplements resulted in a greater increase in muscle mass.

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