L13-16 Flashcards
what is quantitative data?
involves numbers and can be measured objectively; immediately quantifiable
what is qualitative data?
involves words and the data is based on the subjective interpretation of language
what is primary data?
collected directly by the researcher for the purpose of the investigation
what is secondary data?
information that was collected for a purpose other than the current use
what is a meta-analysis?
combining results from a number of studies on a particular topic to provide an overall view
types of presentation of quantitative data?
tables, scattergrams, bar charts
normal distribution is…
symmetrical bell shaped curve
most people located at middle area
positive skew is…
unsymmetrical
concentrated to the left
negative skew is…
unsymmetrical
concentrated to the right
the ends of the curve…
never touch horizontal x-axis
never reach 0
extreme scores always possible
tables
not raw scores been converted (descriptive stats)
scattergrams
show relationship between co-variables
bar chart
shows frequency for discrete (separate) variables
in a bar chart…
space is left between each bar
indicates lack of continuity
what are measures of central tendency?
inform us about central values for a set of data
‘averages’ – ways of calculating typical value
mean, median, mode
what are measures of dispersion?
describes how dispersed or spread out the data items are
range, standard deviation
mean
most sensitive - uses every value
representative of all the data collected (+)
can be distorted by a single extreme value (-)
median
unaffected by extreme scores (+)
any outlier values/extreme values not part of the average measurement (-)
less sensitive than mean, not as representative (-)
mode
unaffected by extreme scores (+)
tells us nothing about other scores in the data set (-)
range
quick and easy to calculate (+)
can be easily distorted by extreme values (-)
standard deviation
takes account of all the scores (+)
more difficult to calculate than the range (-)
percentages
take the no. of pps in a condition
divide by the total no. of pps
times the number you get by 100
e.g. 6/10 x 100 = 60
two types of stats?
descriptive and inferential
what are inferential statistics?
designed to work out probability (p) that particular set of data occurred by chance
not because of IV
sign test…
can only be used when:
one group of pps (repeated measures design)
when data is quantitative
what are descriptive statistics?
analyse data to help describe, show, or summarise it in meaningful way
examples:
measures of central tendency
measures of dispersion
