descriptive statistics Flashcards
what is central tendency?
the different ways of finding averages. It allows us to summarise findings.
what are the three measures of central tendency?
mode
mean
median
when do we use the mean, mode, median?
mean- when there’s no extreme scores
median- 1 or more extreme scores
Mode- can be used on any data but usually when data is categorical
what is the strength and limitation of using a mean?
STRENGTH:
-all scores taken into account therefore more representative of data
LIMITATION:
-can be skewed (distorted) by extreme scores
how is the median found?
all scores are put in order and the middle score identified
what is a strength and limitation of using the median?
STRENGTH:
-not skewed by extreme scores
LIMITATION:
-does not take into account all scores
what is the mode?
the most commonly occurring score in categorical data
what is a strength and limitations of using the mode?
STRENGTH:
-only measure that can be used on all types of data
LIMITATIONs:
-there may be several modes
-ignores all other scores
what are the three types of distribution?
normal, positive and negative
what is normal distribution?
the mean, median and mode are all roughly the same
what is a positive skew?
the median is higher than the mode
what is a negative skew?
median is lower than the mode
what is the range?
top value minus bottom value
what is a strength and limitation of using a range?
STRENGTH:
easy to calculate
LIMITATION:
does not take into account all data and can be skewed by extreme values
why is SD more accurate than a range?
it takes into account the distance every score is from the mean
