Chapter 12: Understanding research results: Description & Correlation

Question 1

What 3 different ways can be used to graph frequency distributions?

Answer 1

• Pie chart
• Bar graph
• Frequency polygon

Question 2

Pie charts are useful in graphing what type of data?

Answer 2

Nominal scale data (no numerical properties, ie gender)

Question 3

Bar graphs are useful in graphing what type of data?

Answer 3

Nominal (no numeric properties, ie gender) and ordinal (orders data low to high, ie class rank)

Question 4

Line graphs/frequency polygons are useful in graphing what types if variables?

Answer 4

Interval (numeric- no absolute 0 ie temperature) and ratio (numeric- absolute 0 ie weight)

Question 5

Why is the standard deviation important?

Answer 5

It gives you a complete picture of the data set; for example, 3 different sets of numbers could have a mean of 15, and without the SD they would all appear the same despite variation in the numbers

Question 6

What is the Empirical Rule/ 68% Rule?

Answer 6

68% of scores fall within +/- 1 deviation units from the mean

Question 7

What does effect size measure?

Answer 7

The magnitude of the effect of the study

Question 8

What are the differences between the Pearson R and effect size?

Answer 8

• Pearson R can only be used with interval and ratio data
• Pearson R is very effected by sample size
• Pearson R values range from -1 to 1, ES ranges from 0 to 1
• Pearson R is measures using weak, moderate, strong, & perfect relationship; ES is measured using small, medium, and large effects

Question 9

What are the measurements of effect size?

Answer 9

.15- small effects
.30- medium effects
.40+- large effects