Research methods Flashcards
DATA HANDLING
BOOKLET 2
What are the different measures of central tendency?
-mean
-medium
-mode
What’s the mean?
Adding up all values and dividing it by total amount of data available
strength / limitations of mean
+
representative of all data as it includes all values
-
Distorted by extreme values
Medium?
the middle value in data when arranged in order
strength / limitation of medium?
+
extreme values do not affect it
-
not all values are included (highest + lowest not taken into account)
Mode?
The most frequently occurring value
strength / limitation of mode?
+
easy to identify / calculate
-
crude measurement - may not be representative of all data
sometimes more than 1 mode
Measure of dispersions?
how spread out the data are
-Range
-Standard deviation (SD)
Range?
Minusing the lowest values from the highest
Strength / limitations of range?
+
easy to calculate
- only takes into account extreme values
(the highest + lowest = not fully representative of spread of all scores)
Standard deviation (SD)?
Single value that tells us how far scores are deviated (spread out) from the mean.
the higher the SD = greater the dispersion/ spread out the data is
Strengths / limitations of SD?
+
more precise measure pf dispersion as it includes all values
better than range as it less affected by extreme values
-
takes longer to calculate
Display of quantitative data?
Graphs - way of displaying data to see trends/patterns in data
-table
-bar chart
-scatter gram / scatter graph
-histogram
-line graph
Table?
shows descriptive statistic as well as raw scores
Bar chart
Type of graph which the frequency of each variable is represented by the height of the bars
Scatter graphs
represents the strength + direction of the relationship between co-variables in a correlation analysis
Histogram
Displays the distribution of a whole continuous data set
there is no space between the columns like a bar chart
Line graph
Displays continuous data and uses points connected by lines to show how something changes in value over time
Distributions
types of distributions?
normal distribution
positive skewed distribution
negative skewed distribution
normal distribution
- the mode, median, mean are all equal
- most values near middle
- the graph is symmetrical
Positive skew distribution
- The mean is HIGHER than the median/mode
- long tail is on (positive) right side of peak
-the curve is on the left
Negative skew distribution
- the mean is LOWER than the median/mode
- Long tail is on the (negative) left side of peak
-the curve is on the right
DESIGNING PSYCHOLOGICAL INVESTIGATIONS
BOOKLET ONE