Health issues Flashcards – AQA GCSE Combined Science: Trilogy (8464) — Biology — Foundation

How can an immune system defect affect susceptibility to infectious diseases?

It makes a person more susceptible to infectious diseases.

What serious disease can viruses living in cells trigger?

Cancer.

What type of condition can an immune reaction initially caused by a pathogen trigger?

An allergy.

How can severe physical ill health affect mental health?

It can contribute to depression or another mental illness.

How does a scatter diagram represent paired values of two variables?

Each pair is plotted as a point, with one variable on each axis.

What trends distinguish positive, negative and no apparent correlation on a scatter diagram?

• Positive: one variable tends to increase as the other increases.
• Negative: one variable tends to decrease as the other increases.
• No apparent correlation: there is no clear trend.

What indicates the strength of an association in a scatter diagram?

How closely the points follow a trend.

Does correlation alone establish that one variable causes the other?

No. Correlation alone does not establish causation.

What is sampling?

Using a subset of a population to obtain information about the population as a whole.

What should be considered when selecting a sample for scientific or epidemiological data?

The population being studied; the sample should be as representative of it as possible.

How can random selection improve a sample?

It can reduce selection bias.

How does increasing sample size generally affect random variation?

It reduces the effect of random variation.

Does increasing sample size by itself correct a biased selection method?

No. A larger sample does not by itself correct biased selection.

What limitation applies to conclusions drawn from a sample?

They are estimates and may not describe the whole population exactly.