Spread of Data (moodle audio book) 10.1 in the book

Question 1

What is the range?

Answer 1

Range is the simplest of these. It is the difference between the highest and lowest values in a distribution.

Question 2

What is variance?

Answer 2

Variance is the sum of the squared deviations about the mean divided by the number of values.

Question 3

What is Standard deviation?

Answer 3

Standard deviation is the square root of the variance. Used when distribution of data is normal.

Question 4

What is Interquartile range?

Answer 4

Interquartile range is the distance between the values which represent the 25 and 75 percentage points in a distribution.
Used when distribution of data is skewed.

Question 5

Symmetrical and normal distributions graph

Answer 5

Normal graph (bell shape) The mean, mode and median are usually similar values

Question 6

Non-symmetrical or skewed distributions graph

Answer 6

Its a graph that is off to one side
You can have negative (it increases)
and positive skew (it decreases)

The mean, mode and median are usually vary alot

Question 7

What is deviation?

Answer 7

Deviation: A deviation is a measurement of the distance from a central value. In a normal distribution the sum of all the deviations in
a sample will add up to zero, because the number of positive and negative deviations will equal out.

Question 8

The mean is always used with standard deviation. True or false

Answer 8

True, The mean is always used with standard deviation

Question 9

The median is always used with the interquartile range, true or false

Answer 9

True, The median is always used with the interquartile range