maths

Question 1

what are the measures of central tendency

Answer 1

mean, median, mode

Question 2

mean

Answer 2

• The mean (or average) is found by adding all values in the data together and dividing by the total number of pieces of data.
  +ve The mean uses all data recorded so it is more representative of the data as a whole.
  -ve Easily distorted by extreme values. - This mean doesn’t really represent the data overall!

Question 3

median

Answer 3

• The median is the middle value in a data set when scores are arranged from lowest to highest.
  +ve Extreme scores do not affect it, Easy to calculate
  -ve Not all scores are included in the final calculation

Question 4

mode

Answer 4

• The most frequently occurring score/value within a data set. You can also have two modes or no mode at all.
  +ve Easy to calculate, The only option for data in categories (nominal). E.g. list of favourite films
  -ve Does not represent the data as a whole

Question 5

central tendency and levels of measurement

Answer 5

Question 6

measures of dispersion

Answer 6

range
standard deviation

Question 7

range

Answer 7

• A calculation of the spread of scores worked out by taking the lowest value from the highest value and adding 1. (add 1 as raw scores are often rounded up/down)
  +ve Easy to calculate
  -ve Only takes into account the two most extreme values – unrepresentative of data set as a whole.

Question 8

standard deviation

Answer 8

• A more sophisticated measure of dispersion.
• This is a single value that tells us how far the scores deviate (move away from) the mean.
• The larger the standard deviation, the greater the dispersion or spread within a set of data.
• A low SD value shows that the data are tightly clustered around the mean. = good
  +ve A much more precise measure of dispersion than range because all values included within calculation.
  -ve Because all values are included, like the mean SD can be distorted by a single extreme value.