3.1-3.2

Question 1

central tendency

Answer 1

is a statistical measure to determine a single score that defines
the center of a distribution.
-The goal of central tendency is to find the single score
that is most typical or most representative of the entire group

Question 2

the mean

Answer 2

also known as the arithmetic average, is computed by adding all the scores in the distribution and dividing by the number of scores.
- the mean for the population is µ=ΣX/N
- the mean for the sample : sample mean=M=ΣX/n

Question 3

the weighted mean

Answer 3

combine two sets of scores and then find the overall mean for the
combined group
weighted mean = (n1/(n1+n2) )x M1 + (n2/(n1+n2))xM2

Question 4

overall mean

Answer 4

overall mean= M= (ΣX1+ΣX2)/n1+n2

Question 5

characteristics of the mean

Answer 5

• changing the value of the score changes the mean ( introducing a new score or removing a score)
  -adding or subtracting a constant changes the mean by the same constant
• dividing or multiplying a constant changes the mean by the same constant