Download Application Exercises

Chapter 6 - Objectives
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Define the term descriptive statistics.
Describe the characteristics of a normal distribution, a positively skewed distribution, and an
negatively skewed distribution.
Explain the concept of central tendency and describe the characteristics of the mean.
Explain the concept of variation and describe the characteristics of a standard deviation.
Explain the relationship between the standard deviation and the normal curve.
Explain the concept of relationship and describe the characteristics of the correlation coefficient
as a measure of relationship. Interpret correlation coefficients in terms of direction and strength.
Define validity as it relates to educational measures, identify five characteristics of validity, and
explain the effect of validity on research.
Identify three sources of validity evidence and give an example of each.
Define reliability of measurement as it relates to educational measures, identify several sources
of measurement error, and explain the effect of reliability of research.
Identify five types of reliability estimates and give an example of each.
Identify the conditions affecting reliability and the ways by which it can be enhanced.
Explain the relationship between validity and reliability.
Chapter 6 – Application Exercises
1.
The following questions are designed to help focus your attention on several important points in
Chapter 6. Answer each question in a succinct manner.
a.
b.
c.
d.
e.
2.
Why is it useful to know the mean of a set of scores? The standard deviation?
Describe the following correlation coefficients in words: -.10, +.10, +.50, and -.80.
Why is it important for researchers to ensure the validity and reliability of a test being
used in their study?
Why are there so many ways to provide evidence of validity?
Which of the types of reliability easiest to use? Why?
Describe the following sets of scores in terms of the mean and standard deviation for both Sets A
and B and the correlation between Sets A and B. Describe these statistics in words.
a.
b.
33
27
31
26
31
28
32
41
29
28
30
35
30
28
32
28
Chapter 6 – Self Assessment Items
1.
The purpose of descriptive statistics is to
a.
b.
c.
d.
organize and summarize data.
assess students.
measure performance.
evaluate observations.
Hint: See Objective 1
2.
Which of the following is a characteristic of the normal curve?
a.
b.
c.
It is symmetric
It is bell shaped
The mean, median, and mode are in the middle of the curve
1
d.
Al of the above
Hint: See Objective 2
3.
A distribution with many high scores and very few low scores can be described as
a.
b.
c.
d.
normal.
positively skewed.
negatively skewed.
all of the above.
Hint: See Objective 2
4.
Measures of central tendency provide
a.
b.
c.
d.
a measure that enables the researcher to study the spread of a distribution.
a numerical index that summarizes important features about a set of scores.
a single index that represents the average performance of a group of students.
information regarding the variability of a distribution.
Hint: See Objective 3
5.
Mr. Harris is comparing two sets of reading scores for his class. He finds that for Test A the
standard deviation is 15, and for Test B it is 6. This means that
a.
b.
c.
d.
the spread of scores in the two distributions is identical.
the scores for Test B are more variable than Test A scores.
the scores are closer to the mean in Test B than in Test A.
the scores in Test A show low variability.
Hint: See Objective 4
6.
Approximately what percentage of scores fall between ±1 standard deviation of the mean?
a.
b.
c.
d.
33%
50%
68%
97%
Hint: See Objective 5
7.
We would expect the relationship between height and weight to be
a.
b.
c.
d.
high and negative.
high and positive.
low and negative.
low and positive.
Hint: See Objective 6
8.
Which of the following is the strongest relationship?
a.
b.
- 0.81
- 0.14
2
c.
d.
+ 0.37
+ 0.78
Hint: See Objective 6
3