✓ Distributions (AO1)

Question 1

What does a normal distribution curve look like?

Answer 1

bell-shaped
- most of the data values in a normal distribution tend to cluster around the mean

Question 2

What does it mean if a data point is further from the mean?

Answer 2

the less likely it is to occur
e.g. height, IQ, blood pressure

Question 3

What does the area under the curve represent?

Answer 3

probability

Question 4

What are the key characteristics of a normal distribution?

Answer 4

• symmetrical
• 50% of the data lies above the mean/ 50% lies below
• unimodal (1 mode = 1 peak)
• tails that approach the x axis but never touch
• mean, median, mode are all equal & represented by the peak of the curve

Question 5

What does a negative skew look like?

Answer 5

___/–\

Question 6

What are the key characteristics of a negative skew?

Answer 6

• contains more high scores than low scores
• large proportions of scores fall after the mean
• median is less than the mode

Question 7

Where are the mode/mean/median of a negative skew?

Answer 7

mode = highest point
mean = the middle point
median = inbetween the mode & median

mean - median - mode

Question 8

What does a positive skew looks like?

Answer 8

/–\___

Question 9

What are the key characteristics of a positive skew?

Answer 9

• contains more low scores than high scores
• large proportion of scores fall below the mean
• median is larger than the mode

Question 10

Where are the mode/mean/median of a positive skew?

Answer 10

mode = highest point
mean = the middle point
median = inbetween the mode & median

mode - median - mean