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

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.

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.

How does a scatter diagram represent paired observations of two numerical variables?

One variable is plotted on each axis; each point represents both values for one observation.

What are the three possible correlation patterns in a scatter diagram?

• Positive: Larger values of one variable tend to occur with larger values of the other.
• Negative: Larger values of one tend to occur with smaller values of the other.
• No clear correlation: There is no apparent trend.

What indicates the strength of a correlation in a scatter diagram?

The closer the points lie to a consistent trend, the stronger the correlation appears.

Does correlation alone establish that one variable causes a change in the other?

No. Correlation alone does not establish causation.