4.2.3.2 DISTRIBUTIONS Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what is normal distribution?

A

a theoretical frequency distribution represented by a normal curve

  • data is symmetrically distributed with no skew
  • when plotted on a graph, the data follows a bell shape with most values clustering around a central region and tapering off as they go further away from the centre
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a skewed distribution?

A
  • the measure of the asymmetry of a distribution
  • its left and right side are not mirror images
  • right-skewed distribution = longer on the right side of the peak (positive skew)
  • left-skewed distribution = longer on the left side of its peak (negative skew)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the characteristics of a normal distribution?

A
  • the mean, median and mode are exactly the same
  • distribution is symmetric about the mean - half the values fall below the mean and half above the mean
  • the distribution can be described by the mean and the standard deviation
    -> the mean is the local parameter while the standard deviation is the scale parameter
    -> it determines where the peak of the curve is centred
    -> increasing the mean moves the curve right, while decreasing it moves the curve left
    -> the standard deviation stretches or squeezes the curve
    -> a small standard deviation = narrow curve
    -> large standard deviation = wide curve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is the characteristic of a skewed distribution?

A

not symmetric - one tail is longer than the other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly