Data Analysis and Graphs

Question 1

What are the 3 types of data ?

Answer 1

Nominal data
Ordinal data
Interval data

Question 2

Define nominal data

Answer 2

Data represented in the form of categories
for eg. How many students in the 6th form drive to school

Nominal data is discrete one item can only appear in one category

Question 3

Define ordinal data

Answer 3

Data which is ordered in some way
Eg. Ask everyone in the class how much they like the 6th form on a scale of 1-10

Does not have equal intervals between each unit
Would not make sense to say that someone who rated the 6th form a 8 enjoys it twice as much as someone who rated
It 4

Question 4

What is a disadvantage of using ordinal data?

Answer 4

Lacks precision as its based on subjective opinion

• psychology questionnaires do not measure something ‘real’ as opposed to measuring height for example
• can be referred to as unsafe which is why it is turned into ranks before we can use statistical test on it

Question 5

Define interval data

Answer 5

Based on numerical scales that include units of equal precisely defined size

Eg. Units of measurements for height , time and temperature

Question 6

Define discrete data ?

Answer 6

The units of measurement cannot be split up
Can only be exact measures

Question 7

Define containing data

Answer 7

Measured using a scale of measurement
Eg. Height and distance

Distance has meaning at all points between the numbers given eg. We can travel a distance of 1.2, 1.85 even 1.632 miles

Question 8

What is measures or central tendency ?

Answer 8

Inform us about central ( or middle ) values for a set of data

The average can be calculated in different ways , each one appropriate for a different situation

Eg. Mean , median , mode

Question 9

Define mean

Answer 9

Is calculated by adding up the data items and dividing but the number of data items

Question 10

Define median

Answer 10

The middle value in a ordered list

Question 11

Define mode

Answer 11

The value that is the most common data item

If two categories or data items have the same frequency the data has two modes

Question 12

What are some advantages of the mean ?

Answer 12

• it is a very sensitive statistic because it takes account of the exact distance between all the values of all the data
• it is representative of all the data

Question 13

What are the disadvantages of the mean ?

Answer 13

• if one of the values is extremely high or low ( anomalous ) then the overall mean can be very distorted and thus misrepresent the data
• it cannot be used with nominal data

Question 14

What are the advantages of using the median ?

Answer 14

• it is not affected by extreme scores so can be useful under such circumstances
• it is easy to calculate
• it is not distorted by any anomalous values

Question 15

What are the disadvantages of using the median ?

Answer 15

It is less sensitive than the mean because the exact values are not reflected in the median

Question 16

What are the advantages of of the mode ?

Answer 16

Unaffected by extreme values and is useful for discrete data and is the on,t method which can be used for nominal data

Question 17

What are the disadvantages of the mode ?

Answer 17

Sometimes there are so many modes that the data cannot be described using this statistic

Question 18

What are “ measures of dispersion “ and how do you calculate it ?

Answer 18

Finds how dispersed or spread out the data items are

Range
Standard deviation

Question 19

What is the range ?

Answer 19

• The arithmetic distance between the top and the bottom value in a set of data
• it is customary to add 1
• the addition of 1 is because the bottom number could represent 0.5 below it and the tip number could be 0.5 above it

Question 20

What is the advantage of the range ?

Answer 20

Easy to calculate

Question 21

What is the disadvantage of the range ?

Answer 21

• effected by extreme values
• it fails to take into account the distribution of numbers
  For eg. It doesn’t indicate whether most numbers are closely grouped around the mean or spread out evenly

Question 22

What is standard deviation ?

Answer 22

A more precise way of measuring the dispersion of the data
This is a measure of the average distance between each data item above and below the mean informing plus and minus values

Smaller the standard deviation the closer together the values in the set are
Larger standard deviation indicates that the values are more spread out from the mean

Question 23

What is a advantage of standard deviation ?

Answer 23

Precise measure of dispersion because it takes into account all the values

Question 24

What is the disadvantage of standard deviation ?

Answer 24

It may hide some of the characteristics of the data set ( eg. Extreme values )

Question 25

Define context

Answer 25

The situations in which a participant says something and the way they are behaving could be important

Could help the interviewer to understand why something was said and the honesty of a statement

Clearly distinguish what is said by the participant from how they interpret it

Question 26

Define selection of data

Answer 26

Can be difficult to summarise
Interviewee could be consulted about what to include and how to present it

Interviewer must be aware of how their feelings about the interviewee lead to bias interpretations

Question 27

Define case study

Answer 27

A in depth study using a range of methods on one person or small group
As it uses a range of different research methods this increases reliability by the process of TRIANGULATION

using a range of different methods is a way of double checking results

Question 28

What is a advantage of case studies ?

Answer 28

• rich data , researchers have the opportunity to study rare phenomena in a lot of detail
• unique cases, can challenge existing ideas and theories and make suggestions for future research

Question 29

What are disadvantages of case studies?

Answer 29

• casual relationships - cause and effect cannot be established
• generalisation
• ethics - informed consent

Question 30

What is a bar chart ?

Answer 30

Used to represent ‘discrete data’ where the data is in categories which are placed on the X axis

• the mean or frequency is on the y axis
• columns do not touch and have equal width and spacing

Question 31

What is a scatter gram ?

Answer 31

Used for measuring the relationship between two variables

• data from one variable is presented on the X axis while the other is presented on the Y axis
• we plot an X on the graph where the two variables meet
• the pattern of plotted points reveals different types of correlation eg. Positive , negative or no relationship

Question 32

What is a histogram ?

Answer 32

Used to represent data on a continuous scale

• columns touch because each one forms a single score ( interval ) on a related scale eg. Time , number of hours of homework students do each week
• scores are placed on the X axis
• the height of the column shoes the frequency of values eg. Number of students in each interval - this

Question 33

What is a line graph ?

Answer 33

Can be used as a alternative to the histogram

• lines show where mid points of each column on a histogram would reach
• particularly useful for comparing two or more conditions simultaneously