Topic 5.1: Practical and Data-Analysis Skills Questions

A frequency graph shows the wing lengths of 80 butterflies grouped into length classes. Which feature of the graph shows the MODAL class?

State the name of the laboratory technique used to amplify (make many copies of) a small sample of DNA.

A student warms an enzyme at 10, 20, 30, 40 and 50 °C and records how long it takes to break down a fixed mass of substrate. Which is the independent variable?

Six maize seedlings have leaf lengths (in mm) of 24, 28, 22, 30, 26 and 26. What is the mean leaf length?

Which piece of equipment is placed inside the eyepiece of a light microscope to measure the size of a cell directly?

A correlation coefficient of r = 0.02 is found between shoe size and exam score in adults. What does this value indicate?

Four replicate counts of yeast colonies on a plate give 48, 52, 49 and 51. What is the mean number of colonies?

State the name of the device fitted inside the eyepiece of a light microscope that is used to measure the size of a cell.

State what a higher value of Simpson's reciprocal diversity index ($D$) indicates about a community.

A student compares the number of red-flowered and white-flowered plants from a cross against an expected 3 : 1 ratio. State which statistical test should be used to decide whether the observed numbers differ significantly from the expected ratio.

A table records the mean browning index of cut apple slices after 30 minutes for five antioxidant dip concentrations (arbitrary units): 0% dip = 8.4, 1% = 5.1, 2% = 3.0, 3% = 1.8, 4% = 1.9. State the dip concentration that gave the lowest browning index.

A table gives the mean dry mass (g) of four wheat varieties: W = 3.8, X = 4.6, Y = 4.1, Z = 3.5. Which variety should be identified as having the greatest mean dry mass?

To calculate the percentage change in a measurement, by which value must the change be divided?

In the Lincoln (capture–mark–recapture) index $N = \dfrac{n_1 \times n_2}{n_3}$, what does $n_3$ represent?

A bar chart shows mean leaf area for plants grown in shade (24 cm²) and in full sun (40 cm²). State the difference in mean leaf area between the two conditions.

Four students each report the magnification of the same micrograph using the same correctly measured scale bar. Whose answer is written correctly?

An ecologist wants to record how plant species change from the edge of a woodland into a neighbouring open field. Which sampling method shows this change ALONG the set distance?

On a bar chart of mean results, each bar is capped with an error bar drawn at ± one standard deviation. State what these error bars represent.

Which instrument is used to measure the rate of respiration of a small organism such as a germinating seed or a woodlouse?

A forensic scientist has only a tiny trace of DNA from a crime scene and needs millions of copies before it can be analysed. Which technique should be used?