GRAVETTER_CH03_THE MEAN

Question 1

The term for a sum of scores divided by the number of scores in a distribution.

Answer 1

Mean

Question 2

TRUE OR FALSE: In general, we use Greek letters to identify characteristics of a population (parameters) and letters of our own alphabet to stand for sample values (statistics).

Answer 2

TRUE.

Question 3

TRUE: The mean balances the distances between scores.

Answer 3

TRUE.

It acts like a fulcrum in this case. That is, the total distance (value) below the mean is the same as the total distance (value) above the mean.

Question 4

What type of mean is it when two sets of scores are combined and we find the overall mean for the combined group?

Answer 4

The weighted mean.

Question 5

What are two values needed for the weighted mean?

Answer 5

Overall sum of scores for the combined group and total number of scores in the combined group

M= ΣX1 + ΣX2
—————-
n1+n2

where M is overall mean

Question 6

TRUE OR FALSE: Changing the value of any score will change the mean.

Answer 6

TRUE.

Question 7

THINK! Adding a new score to a distribution, or removing an existing score, will usually change the mean. When is the exception for this?

Answer 7

When the new or removed score is exactly equal to the mean.

Question 8

TRUE OR FALSE: If every score in a distribution is multiplied by (or divided by) a constant value, the mean will change in the same way.

Answer 8

TRUE.