Research Methods: Descriptive Statistics KR Flashcards
How do we analyse Quantitative data
by using descriptive statistics
What type of data does descriptive statistics analyse?
Quantitative data
Descriptive statistics analyses quantitative data. What two ways of doing this?
Measures of dispersion and measures of central tendency
What is meant by measures of central tendency?
any measure of the average value in a set of data
What is meant by measures of dispersion?
the spread of scores
Name the three ways in which we can uses measures of central tendency to analyse quantitative data
Mean, Median, Mode
Mean median and mode are apart of which descriptive statistic?
measures of central tendency
Summarise Mode as a measure of central tendency
most common score
Summarise Median as a measure of central tendency
central/middle score in a ranked list
Summarise Mean as a measure of central tendency
Mathematical average
True or False: there can be only one mode in a data set
False: there can be more than one mode in a data set
Which level of measurement uses Mode?
nominal
Which measure of central tendency is used with nominal data?
Mode
How is mode calculated?
take the most common frequency
A03: What is a strength of mode?
it is easy to calculate and less prone to distortion by extreme scores
A03: Why is mode less prone to distortion by extreme scores?
it doesn’t take into account all of the scores, only the most common
A03: What is a weakness of mode?
it doesn’t take account of all scores
A03: Why is it a weakness of mode that it doesn’t take into account all scores?
the data may be less accurate as we exclude extreme scores
A03: Why is it a weakness if we ignore extreme scores in mode?
it limits our understanding of behaviour
A03: What is a further weakness of mode?
not as useful if there is more than one mode in a data set
A03: Why is mode not as useful if there is more than one mode in a data set?
it affects how we interpret the data
How do we calculate the median score?
rank the scores in order and pick the central score
What should we do if there are two central numbers when calculating the median score?
if there are two central scores, add together and divide by 2
A03: What is a strength of using the median?
easy to calculate and not effected by extreme scores
A03: Why is the median not affected by extreme scores?
it doesn’t take into account all values only the central score
A03: What is a weakness of using the median?
it is not as sensitive as mean
A03: why is the median not as sensitive as the mean?
it doesn’t take into account all values only the central score
How do we calculate the mean?
All scores added up and divided by the total number of scores
A03: what is a strength of using the mean?
it is the most accurate and sensitive measure of central tendency
A03: Why is the mean the most accurate and sensitive measure of central tendency?
it takes into account all values/scores
A03: What is a weakness of using the mean?
it is affected by extreme scores
A03: Why is the mean affected by extreme scores?
it takes all the values into account
A03: If the mean is affected by extreme scores, what can this do to the data?
It can result in misleading interpretations of the results
What methods do we use to measure the level of dispersion in data?
standard deviation and range
What do we use standard deviation and range for?
measures of dispersion
What is meant by range?
spread of scores from smallest to largest
How do we calculate the range?
subtract the lowest value from the highest value and add 1
What level of measurement uses range?
ordinal
What measure of dispersion is involved in ordinal data?
range
A03: what is a strength of using range?
it is easy and quick to calculate
A03: Why is the range quick and easy to calculate?
it only uses 2 pieces of the data to calculate
A03: What is a weakness of using the range?
it can be distorted by extreme scores
A03: Why can the range be distorted by extreme scores?
it only takes into account the smallest and largest values
A03: By only taking into account the smallest and largest values, what could this do to the interpretation of data when using range?
it provides an inaccurate range and therefore an inaccurate interpretation
What is meant by standard deviation?
the spread of data around the mean
How do we interpret a large standard deviation?
the larger the spread of data around the mean
What does a large spread of data show us?
that there is less consistency in scores and more individual differences
Why does a large spread of data show us that there is more individual differences?
because less participants have met the mean score which shows that the IV has not affected participants in the same way
How do we interpret a small standard deviation?
a smaller spread of data around the mean
What does a small spread of data show us?
that there is more consistency and less individual differences
Why does a smaller standard deviation show us more consistency in data?
because all the scores are clustered around the mean
What level of measurement uses standard deviation?
interval data
What measure of dispersion does interval data use?
standard deviation
What is meant by 1 standard deviation?
they are 1 interval/ standard deviation away from the mean score
A03: what is a strength of using standard deviation?
it is more precise and sensitive measure
A03: Why is standard deviation more sensitive and precise?
it uses all the scores making it a more accurate measure of dispersion than range
A03: Why is standard deviation less likely to be distorted by extreme scores?
it focusses on the distance of each score from the mean rather than from the highest to the lowest
A03: what is a weakness of using standard deviation?
it is more complicated and time consuming
A03: Why is standard deviation complicated and time consuming?
the calculation is lengthy
How are descriptive statistics displayed
in a graph/table
Work out the Mean, Median, Mode and Range from the data below
Mean: 45
Median: 30.5
Mode: 12
Range: 86
Work out the Mean, Median, Mode and Range from the data below
Mean: 69.7
Median: 82
Mode: 92
Range: 60
Work out the Mean, Median, Mode and Range from the data below
Mean:17.5
Median: 4
Mode: 4
Range:74
Work out the Mean, Median, Mode and Range from the data below
Mean: 42.5
Median: 28.5
Mode: 11
Range: 92
Work out the Mean, Median, Mode and Range from the data below
Mean: 43.1
Median: 43.5
Mode: 65
Range: 45
Work out the Mean, Median, Mode and Range from the data below
Mean: 50.5
Median: 39
Mode: 34
Range: 52
Work out the Mean, Median, Mode and Range from the data below
Mean: 23.3
Median:22
Mode: 22
Range:5
Work out the Mean, Median, and Range from the data below
Mean:57.8
Median:67
Range:86
Work out the Mean, Median, Mode and Range from the data below
Mean:42.8
Median:44
Mode:61
Range:48
Work out the Mean, Median, Mode and Range from the data below
Mean:36.7
Median:34.5
Mode:32
Range:17
Work out the Mean, Median, Mode and Range from the data below
Mean:18
Median:18
Mode:18
Range:8
Work out the Mean, Median, and Range from the data below
Mean:28.3
Median:23.5
Range:51
