distributions

Question 1

What is a distribution in psychological research?

Answer 1

A distribution shows how data are spread across values in a data set. It is often represented as a frequency distribution, such as in a histogram.

Question 2

What is a normal distribution?

Answer 2

A normal distribution is a bell-shaped curve that is symmetrical around the mean. In a perfectly normal distribution:
• Mean = Median = Mode
• Most scores cluster around the centre
• Fewer scores appear at the extremes

Question 3

What are the characteristics of a normal distribution?

Answer 3

• Symmetrical shape
• Single peak at the mean
• 68% of scores fall within 1 SD of the mean
• 95% within 2 SDs
• 99.7% within 3 SDs

Question 4

What is a skewed distribution?

Answer 4

A skewed distribution is asymmetrical, where the data leans to one side. The mean, median, and mode differ.

Question 5

What is a positively skewed distribution?

Answer 5

In positive skew:
• The tail is to the right
• The mean > median > mode
• Most scores are low, with a few high outliers
Example: Salary distribution in a company

Question 6

What is a negatively skewed distribution?

Answer 6

In negative skew:
• The tail is to the left
• The mean < median < mode
• Most scores are high, with a few low outliers
Example: Easy test where most score high

Question 7

How do skewed distributions affect measures of central tendency?

Answer 7

• The mean is most affected by extreme scores
• The mode stays central, and median shifts slightly
• In skewed data, the mean is pulled toward the tail

Question 8

How should you interpret a distribution graph?

Answer 8

1. Identify if it’s normal or skewed
   
   2. Look at the position of the tail
   3. Consider how it affects central tendency and spread