data analysis: descriptive statistics

Question 1

what are the measures of central tendencies

Answer 1

these are”averages” which give us information about the most typical values in are of data. There are three of these to consider:

• mean
• medium
• mode

Question 2

what is an advantage of the mean

Answer 2

the mean, also known as the average, is the most sensitive of the measures of central tendency as it includes all of the scores/ values in the data within the calculation

This means it is representative of the data as a whole

Question 3

what is a limitation of the mean

Answer 3

the mean can be easily distorted by extreme values

e.g. in the list 5,7,7,8,9,11,12,14,15,17 if we replace 17 with 98, the mean becomes 18.8 which does not represent the data overall

Question 4

what is the medium

Answer 4

the medium is the middle number in a data set when scores are arranged from lowest to highest

in an even list, we half the tow half numbers

Question 5

what are some advantage of the medium

Answer 5

extreme values do not affect it so even if we replaced 17 with 98 ( as seen with the list in the mean example), the medium would stay the same

It is easy to calculate once the values are in order

Question 6

what is a disadvantage of the medium

Answer 6

the medium is less sensitive than the mean as not all scores are included in the final calculation

Question 7

what is the mode

Answer 7

the mode is the most frequently occurring score/ value within a data set
In some data sets there may be two modes ( bi - modal) or no mode if all the scores are different

Question 8

what is a strength of the mode

Answer 8

for some data (data categories) the mode is the only method you can use

e.g. if you asked your class to list their favourite desserts, the only way to identify the most “typical” or the average value would be selecting the modal group

Question 9

what is a limitation of the mode

Answer 9

although the mode is easy to calculate,it is still a very crude measure

Question 10

what are measures of dispersion

Answer 10

measures of dispersion are based on the spread if scores

Basically how far scores vary and differ from one

Question 11

what are the different measures of dispersion

Answer 11

Range

Standard Deviation

Question 12

how do we calculate the mean

Answer 12

the range is calculated by this equation: highest value - lowest value + 1

we add 1 as a mathematical correction that allows for the fact that raw scores often rounded up ( or down) when they are recorded within research - essentially, the addition of 1 counts for the margin of error

Question 13

what is a strength of the range

Answer 13

it is easy to calculate

Question 14

what is a limitation of the range

Answer 14

it only takes ito account the two most extreme values, and this nay be unrepresentative of the data set as a whole

Question 15

what is standard deviation

Answer 15

standard deviation is a more sophisticated measure of dispersion

This is a single value that tells is how far scores “deviate”form the mean

Question 16

what does it mean when a set of data has a large standard deviation

Answer 16

the larger the standard deviation, the greater dispersion
or spread within a set of data is

-a large standard deviation value reflects the fact that not all participants were affected by the IV in the same way because the data are quie widely spread.

This may be because there are a few anomalous results in the data

Question 17

what does it mean when a set of data has a low standard deviation

Answer 17

a low standard deviation value reflects that the data are tightly clustered around the mean, which might imply that all participants responded in a fairly similar way

Question 18

what is a strength of standard deviation

Answer 18

more precise measure of dispersion than the range as it includes all the values in the final calculation

Question 19

what is a limitation of standard deviation

Answer 19

as it includes all the values, like the mean, it can be distorted by a single extreme value