1. MEASURES OF CENTRAL TENDENCY Flashcards
1
Q
- What is the Mode?
A
- this is the most common value of the data variable
2
Q
- What is the Median?
A
- this is the middle point of the distribution
- it is the value such that half of the observed values are
smaller than the median
AND the other half of the observed values are larger
than the median
3
Q
- What is the Mean also known as?
A
- the Arithmetic Mean
- the Average
4
Q
- How do we calculate the Mean?
A
- we add all the values together
- we then divide them by the number of values there are
5
Q
- What does the Mean play a very important role in?
A
- it plays a very important role in Normal Distribution
- this is because most values are clustered around the
mean
6
Q
- In Normal Distribution, what can be said about the measures of Central Tendency?
A
- the Mean, Median and Mode are all equal to each
other - the Arithmetic Average tends to be he most common
value and the Centre of Distribution
7
Q
- Provide a definition for Dispersion?
A
- how much the variable varies and spreads around the
central location
8
Q
- How is the Range calculated?
A
- we take the Maximum Value (the largest one)
AND we subtract the Minimum Value (the smallest one)
from it
9
Q
- What can be said about the benefits of the Range?
A
- it is easy to compute
10
Q
- What are the disadvantages of the Range?
A
- it is not very informative
- it considers only two observations
(the smallest and the largest) - it will be highly affected by extreme values
11
Q
- How are Quantiles deduced?
A
- the values are sorted from minimum to maximum
- the values are then split into parts
12
Q
- What are Tertiles?
A
- this is the splitting of a numeric variable into 3
categories
13
Q
- What are Quartiles?
A
- this is the splitting of a numeric value into 4 categories
14
Q
- What are Quintiles?
A
- this is the splitting of a numeric value into 5 categories
15
Q
- What is the Q1 Value?
(the first Quartile value)
A
- this is the value at which 25% of the observed values
are smaller than it - it is also known as the 25th Percentile
16
Q
- What is the Q2 Value?
(the second Quartile value)
A
- this is the value at which 50% of the observed values
are smaller than it - it is also known as the 50th Percentile
- it is the same as the Median
17
Q
- What is the Q3 Value?
(the third Quartile value)
A
- this is the value at which 75% of the observed values
are smaller than it - this means that only 25% of the observed values are
greater than it - this is also known as the 75th Percentile
18
Q
- Does this diagram make sense?
A
- yes
19
Q
- What is the Inter Quartile Range (IQR)?
A
- this is worked out by subtracting the Q1 value from the
Q3 value - it is the width of the range that contains 50% of the
Central Data
20
Q
- What can be said about the values in a Normal Distribution situation?
A
- the values cluster around the mean
- these values can be more or less spread out around
the mean
21
Q
- What is the Standard Deviation?
A
- it is the typical spread or variation around the mean
- it is the standard dispersion around the mean
- it is written as: āsā
22
Q
- How do Standard Deviation and the Variance relate to one another?
A
- the Standard Deviation is the square root of the
Variance - the Variance is another measure of Dispersion
23
Q
- In which two types of graphs do we present Numeric Data?
A
- Box-Plot
- Histogram
24
Q
- What is a Box Plot?
A
- it is a 5 number summary
IT INCLUDES:
- the Minimum (the smallest value)
- the Q1 (first quartile value)
- the M (the median)
- the Q3 (the third quartile value)
- the Maximum (the largest value)
25
25. What is a Histogram?
- this is a summary graph for a single numeric value
- the range of the values that a variable can take is
divided into intervals of equal size
26
26. What does a Histogram show?
- it shows the number of individual data points that fall
in each interval
27
27. Does this Histogram make sense?
