Chapter 3 Leslie M. Jones ORGANIZING AND GRAPHING DATA Circle the correct answer: (Answer is highlighted with red color) 3.1 Class intervals are usually created when the range of the scores is high ....

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Chapter 3


Leslie M. Jones


ORGANIZING AND GRAPHING DATA


Circle the correct answer: (Answer is highlighted with

red

color)

3.1 Class intervals are usually created when the range of the scores is
high
.

3.2 Tables that are used to indicate the number of scores at or above a given score are called
class intervals
tables.
3.3 A graph where each bar represents a category, and the bars are typically ordered by their height, is called a
bar diagram.
3.4 The two graphs that are used to depict frequency distributions are the frequency polygon and the
histogram.
3.5 In drawing histograms, the lower scores are recorded on the
left
side of the scores axis (the horizontal axis).
3.6 Frequency polygons are likely to look smoother as the number of scores
increases.
3.7 The graph most likely to be used to show data found in a cumulative frequency table is the
ogive.

Note: An ogive (a cumulative line graph) is best used when you want to display the total at any given time. (Total means cumulative).


Reference: John Wiley & Sons (2012). Ogive. Retrieved May 23, 2012 from http://www.cliffsnotes.com/study_guide/Ogive.topicArticleId-267532,articleId-267437.html.
3.8 The type of graph that can best show how different subgroups in a distribution relate to each other and how the proportions of the different subgroups add up to 100% is the
pie graph.
3.9 The median, skewness, and spread of a distribution are best depicted using a
box plot.

Chapter 4


MEASURES OF CENTRAL TENDENCY


Fill in the blanks:

4.1 The score that repeats the most often in a distribution is called the ______.

MODE

4.2 The descriptive statistic used the most in inferential statistics as a measure of central tendency is the _______________.
(MEAN)

4.3 The measure of central tendency used with nominal scale data is the ______.(MODE)

4.4 To find the mean of a sample (X), sX
(the sum of the scores) is divided by _______.

NO. OF CASES


Circle the correct answer:

4.5 In a positively skewed distribution, the majority of the scores cluster above/below the ________.
(MEAN)

4.6 The mode and the mean have the same values in distributions that are
normal.
4.7 Distributions with few scores are
less
likely to have a mode than distributions with many scores.
4.8 Which measure of central tendency would be the most appropriate for summarizing the following quality scores? Explain your choice. 13, 14, 10, 38, 11, 12, 16, 15

Note: The computed mean here is

16.125. Looking at the data, it will show that the mean of 16.125 is not the best way to use since there are more data that range from 13 to 12. The best measure of central tendency for this data is the median. The computed median of 13.5 is compatible with the data ranges because it falls right at the center. This is evident when data is arranged from highest to lowest (10, 11, 12, 13, 14, 15 16, 38).


4.9 What is the difference between
X
and u? How are they related to each other?

Note: µ or the population mean is simply the average of all the items in a population.

The sample mean (often represented by the symbol XBAR) is the average of all the items in a sample.

Reference: http://www.childrensmercy.org/stats/definitions/mean.htm

Note: The two are related because the sample originates from the population. They have basically the same formula. Sample mean uses small n while the population mean uses big N.

4.10 A distribution of 10 scores has a mean of 6. Following are 9 scores of this distribution. Which score is missing (remember that the mean should be 6)? 4, 8, 10, 5, 9, 3, 6, 7, 3

Note: The missing score is 5. Try adding 5 in

4, 8, 10, 5, 9, 3, 6, 7, 3. The resulting mean would be 6.

4.11 When the sum of a group of scores is 280 and the mean of the scores is 7, how many scores are in the distribution?

Note: Putting this down into the mean formula, the result would be:


Mean = ?X / n


Inserting the given data, the result would be:


7 = 280/n


By transposition, we get:


7n=280


n = 280/7


n = 40, the number of scores in the distribution is 40.


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Answered Same DayDec 23, 2021

Answer To: Chapter 3 Leslie M. Jones ORGANIZING AND GRAPHING DATA Circle the correct answer: (Answer is...

Robert answered on Dec 23 2021
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Leslie M Jones
Assignment 3
Chapter 8
CORRELATION
Fill in the blanks:

8.1. The magnitude of the correlation is indicated by the correlation _____
which can range from -1.00 to +1.00.

Answer: Coefficient- to be explained shortly.
8.2. The most common and efficient way to present the correlations of several
variables with each other is by using a(n) ______ table.
Answer: Typically called a correlation table.

ANOVA summary table
8.3. The correlation between two variables can be shown graphically by a

________.

Answer: Scatter plot, typically by plotting a line of best fit.
8.4. The null hypothesis predicts that the correlation coefficient is equal to
_______.
Answer: Zero, hence the “null” hypothesis.
8.5. The Spearman rank order correlation is used when the variables to be
correlated are measured on a(n) ______ scale.
Answer: Ordinal, spearman rank is good for ordered variables
Circle the correct answer:

8.6. The hypothesis that states that r0 is an example of a(n) alternative/null
hypothesis.
Answer: This is an alternative hypothesis, and two sided as the alternative could be
either higher or lower than zero.


8.7. When an increase in one variable is associated with a decrease in the
other variable, the correlation between these two variables is
positive/negative.

Answer: This is a negative correlation, try plotting two variables, one increasing while
the other decreasing- this is a negative correlation (a down sloping line, negative slope).
8.8. In order to use the Pearson product-moment correlation, the variables to be
correlated should be measured on an ordinal/interval scale.

Answer: In this case, the Pearson correlation requires interval scale variables
8.9. When the points on a scattergram go from the bottom left to the top right
they represent a positive/negative correlation.

Answer: Positive correlation, try plotting, you’ll find increases in variable follow increases
in the other.
8.10. The true correlation between two variables may be underestimated when
the variance of one of the variables is very high/very low.
Answer: Low- if there is low variance, we have only a small range of data points. Higher
variance is needed in order to observe correlation.

Very High
8.11. When the null hypothesis is rejected at p<.001, it means that the chance
that r=0 is very small/very high.
Answer: Very small chance that “r=0”. In this case, you’ll need to understand the normal
distribution. Simply put, the p-value is the probability that a value at least as extreme as
the actual “r” observed could happen if the true value of “r” was zero. The probability of
this is less than one in 10,000.
8.12. The null hypothesis is rejected when the obtained correlation coefficient is
higher/lower than the critical value.

Answer: Higher, I’ll attach a description of this question in another document.
Lower
Answer/compute the following questions:

8.13 Which correlation coefficient (a or b) shows a stronger relationship
between the two variables being correlated?
a. X1&Y1: r = .85
b. X2&Y2: r = -.94
Answer: “b” while the correlation is negative, it a “stronger” negative correlation.
8.14. Following are two scattergrams (in Figure A and in Figure B). Four
different correlation coefficients are listed under each scattergram. Choose
the coefficient that best matches each scattergram.
Y Y

  
   
   
   
    
   
   
   
   
  
X X

Figure A Figure B

A1. r= .50 B1. r= -.57
A2. r= .78 B2. r= .92
A3. r= -.10 B3. r= .38
A4. r= -.89 B4. r= -.91

Answer: In figure “A”, it looks like there is a weak positive correlation. Firstly, we know
“r” must be positive. Intuitively, we know an “r” of nearly .8 would have points closer
together, so we’ll go with A1. In figure B, we have a strong negative correlation. We’ll go
with B4 in this case.

A1. r= .50 and B3. r= .38

8.15 Following is a scattergram showing the scores of 8 statistics students on
two tests, X and Y. Each of the first 7 students is represented by a dot and their
scores are listed in the table that follows. Use the scattergram to find the scores of
student #8 on test X and test Y. The location of this student on the scattergram is
represented by a large dot (•) next to number 8.
Y
1 4
4  
5 2
3  
6 8
2  

7 3
1  
X
1 2 3 4 5
Student # X Y

1 2 4
2 3 3
3 2 1
4 5 4
5 2 3
6 2 2
7 1 1
8 3 2 (Simply read off the graph)
8.16 What do these two...
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