1. MEASURES OF CENTRAL TENDENCY

Question 1

1. What is the Mode?

Answer 1

• this is the most common value of the data variable

Question 2

2. What is the Median?

Answer 2

• 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

Question 3

3. What is the Mean also known as?

Answer 3

• the Arithmetic Mean
• the Average

Question 4

4. How do we calculate the Mean?

Answer 4

• we add all the values together
• we then divide them by the number of values there are

Question 5

5. What does the Mean play a very important role in?

Answer 5

• it plays a very important role in Normal Distribution
• this is because most values are clustered around the
  mean

Question 6

6. In Normal Distribution, what can be said about the measures of Central Tendency?

Answer 6

• 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

Question 7

7. Provide a definition for Dispersion?

Answer 7

• how much the variable varies and spreads around the
  central location

Question 8

8. How is the Range calculated?

Answer 8

• we take the Maximum Value (the largest one)
  AND we subtract the Minimum Value (the smallest one)
  from it

Question 9

9. What can be said about the benefits of the Range?

Answer 9

• it is easy to compute

Question 10

10. What are the disadvantages of the Range?

Answer 10

• it is not very informative
• it considers only two observations
  (the smallest and the largest)
• it will be highly affected by extreme values

Question 11

11. How are Quantiles deduced?

Answer 11

• the values are sorted from minimum to maximum
• the values are then split into parts

Question 12

12. What are Tertiles?

Answer 12

• this is the splitting of a numeric variable into 3
  categories

Question 13

13. What are Quartiles?

Answer 13

• this is the splitting of a numeric value into 4 categories

Question 14

14. What are Quintiles?

Answer 14

• this is the splitting of a numeric value into 5 categories

Question 15

15. What is the Q1 Value?
    (the first Quartile value)

Answer 15

• this is the value at which 25% of the observed values
  are smaller than it
• it is also known as the 25th Percentile

Question 16

16. What is the Q2 Value?
    (the second Quartile value)

Answer 16

• 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

Question 17

17. What is the Q3 Value?
    (the third Quartile value)

Answer 17

• 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

Question 18

18. Does this diagram make sense?

Answer 18

• yes

Question 19

19. What is the Inter Quartile Range (IQR)?

Answer 19

• 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

Question 20

20. What can be said about the values in a Normal Distribution situation?

Answer 20

• the values cluster around the mean
• these values can be more or less spread out around
  the mean

Question 21

21. What is the Standard Deviation?

Answer 21

• it is the typical spread or variation around the mean
• it is the standard dispersion around the mean
• it is written as: “s”

Question 22

22. How do Standard Deviation and the Variance relate to one another?

Answer 22

• the Standard Deviation is the square root of the
  Variance
• the Variance is another measure of Dispersion

Question 23

23. In which two types of graphs do we present Numeric Data?

Answer 23

1. Box-Plot
2. Histogram

Question 24

24. What is a Box Plot?

Answer 24

• 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)

Question 25

25. What is a Histogram?

Answer 25

• 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

Question 26

26. What does a Histogram show?

Answer 26

• it shows the number of individual data points that fall
  in each interval

Question 27

27. Does this Histogram make sense?

Answer 27