4.3 measures of central tendency

Question 1

define what is meant by a ‘measure of central tendency’.

Answer 1

a form of estimation of a mid-point/average in a set of data.

Question 2

what are the three measures of central tendency?

Answer 2

1. mean
2. median
3. mode

Question 3

define ‘mean’ (1).

Answer 3

the average that is shown by all scores in the data set when they are
divided by n.

Question 4

explain how to calculate mean (2).

Answer 4

1)calculate by adding all the scores in the data set together
2)divide by the total number of scores (n)

Question 5

define ‘median’ (1).

Answer 5

the mid-point in a set of data that has been placed in order.

Question 6

explain how to calculate median (2).

Answer 6

• if there is an odd number of scores, arrange all of the scores in the
  data set in numerical order, select the middle value.
• if there is an even number of scores, then arrange all the scores in the data set in numerical order, add together the two middle values, divide this by two

Question 7

define ‘mode’ (1).

Answer 7

the most common value within a set of data.

Question 8

explain how to calculate mode(2).

Answer 8

• count the frequency of each score achieved in the data set
• the score(s)
  with the highest frequency is/are the modal score(s)

Question 9

define what is meant by a ‘measure of dispersion’.

Answer 9

a measure that shows the spread of data, whether
it is tightly clustered or has a broader spread.

Question 10

define ‘range’ (1).

Answer 10

a value that shows the spread of data, representing the difference between
the lowest and highest scores.

Question 11

explain how to calculate range. (1)

Answer 11

take the lowest score from the highest score and add one.

Question 12

define ‘standard deviation’ (1).

Answer 12

a value (1)that represents the amount of
variation of results from the mean score (2).

Question 13

explain how to calculate standard deviation. (3)

Answer 13

1) Calculate the sum of x, minus the mean, squared using a table.
2)Divide
this by n-1.
3) take the square root of this answer to find the standard
deviation