Gaussian Distribution

Question 1

GD arises when…

Answer 1

Arises when many random factors create variability.
Many values end up near the mean. Very few end up
far from the mean. The scatter is symmetrical.
-creates a bell-shaped curve when plotted as frequency
distribution.
-applies well to continuous data when scatter is the result
of many independent causes.

Question 2

parameters of GD

Answer 2

mean and sd

Question 3

horizontal axis of GD

Answer 3

values

Question 4

vertical axis of GD

Answer 4

relative frequency

Question 5

If you assume that data is sampled from a
population with a Gaussian distribution, then this
is why you can assume

Answer 5

that approximately 2/3 of

the samples should occur with 1 SD of the mean.

Question 6

If the data is not sampled from a population with

a Gaussian distribution, then you

Answer 6

cannot assume
that approximately 2/3 of the samples should
occur with 1 SD of the mean.

Question 7

The Standard Normal Distribution

Answer 7

• The mean = 0

* And the SD = 1

Question 8

Standardization:

Answer 8

a way of scaling
variables so that
different
variables,
measured in
different units,
can be
compared.

Question 9

The most common form of standardization involves

Answer 9

subtracting the mean and dividing by the standard

deviation.

Question 10

Transform each value:

Answer 10

z = (Value – Mean)/SD
Z = the number of SD away from the mean

Question 11

The Central Limit Theorem:

Answer 11

the means of
many random samples will approximate a
normal distribution, even if the samples are
taken from a population that does not have
a normal distribution.
• Thus, when comparing means, it can be
appropriate to assume a normal distribution
under a wide range of circumstances.