Question 1

Discuss the concepts of control variables and trivariate tables.What are three limitations of trivariate tables?

Accepted Answer

● In order to meet all the conditions needed for causality,researchers want to "control for" or see whether an alternative explanation explains away a causal relationship.If an alternative explanation explains a relationship,then the bivariate relationship is spurious.Alternative explanations are operationalized as third variables,which are called control variables because they control for alternative explanations.
● A trivariate table has a bivariate table of the independent and dependent variable for each category of the control variable.These new tables are called partials.The number of partials depends on the number of categories in the control variable.Partial tables look like bivariate tables,but they use a subset of the cases.Only cases with a specific value on the control variable are in the partial.Thus,it is possible to break apart a bivariate table to form partials,or combine the partials to restore the initial bivariate table.
● Trivariate tables have three limitations.First,they are difficult to interpret if a control variable has numerous categories.Second,control variables can be at any level of measurement,but interval or ratio control variables must be grouped (i.e.,converted to an ordinal level),and how cases are grouped can affect the interpretation of effects.Finally,the total number of cases is a limiting factor because the cases are divided among cells in partials.

Question 2

Is a Type I or Type II error more likely if a 0.05 level is used? Explain.

Accepted Answer

● Type I error: Falsely accepting the null hypothesis when in fact there is a causal relationship (usually occurs at a more precise level such as at the 0.01 level)
● Type II error: Indicates a relationship when in fact no causal relationship exists (random factors actually caused the results and usually occurs at the 0.10 level)
● 0.05 level is a compromise between Type I and Type II errors.

Question 3

Describe each of the three measures of central tendency.What are the main differences between them? How are they affected by a normal versus a skewed distribution of data?

Accepted Answer

● Mean: A measure of central tendency for one variable that indicates the arithmetic average (i.e.,the sum of all scores divided by the total number of scores)
● Median: A measure of central tendency for one variable indicating the point or score at which half the cases are higher and half are lower 
● Mode: A measure of central tendency for one variable that indicates the most frequent or common score 
● Skewed distribution: If the frequency distribution forms a "normal" or bell-shaped curve (normal distribution),the three measures of central tendency equal each other.If the distribution is a skewed distribution (i.e.,more cases are in the upper or lower scores),then the three will not be equal.If most cases have lower scores with a few extreme high scores,the mean will be the highest,the median in the middle,and the mode the lowest.If most cases have higher scores with a few extremely low scores,the mean will be the lowest,the median in the middle,and the mode the highest.

Question 4

A researcher wants to express the middle of a distribution of numbers whereby half the cases are higher and half the cases are lower than the middle value.What statistical measure should the researcher use?
A)Mean
B)Median
C)Mode
D)Standard deviation
E)Correlation

Accepted Answer

The median is the best choice as it represents the middle value in a distribution, whereby half the values are above and half are below. The mean can be influenced by extreme values and the mode is not always a good representation of the middle of a distribution. The standard deviation and correlation do not represent the middle value of a distribution.

Question 5

Calculate the mean for the following six shoe sizes: 9,10,10,8,12,11.
A)8
B)8)5
C)9
D)9)5
E)10

Accepted Answer

The answer of Calculate the mean for the following six...

Question 6

Describe four ways a researcher can display information about univariate statistics.

Accepted Answer

The answer of Describe four ways a researcher can display...

Question 7

Which neighbourhood(s)has an income distribution resembling a skewed curve?
A)Glenbrook
B)Meadowbrook
C)Elmbrook
D)Glenbrook and Elmbrook
E)Meadowbrook and Elmbrook

Accepted Answer

Both Glenbrook and Elmbrook have an income distribution resembling a skewed curve, as indicated by the graph provided in the text. Meadowbrook, on the other hand, has a more symmetrical income distribution.

Question 8

Describe,as simply as possible,what is meant by the statement "It is statistically significant at the 0.05 level."

Accepted Answer

The answer of Describe,as simply as possible,what is meant by...

Question 9

What are two ways in which statistical relationships can be described? Provide an example for each one.

Accepted Answer

The answer of What are two ways in which statistical...

Question 10

Why is knowing the variability or dispersion of a variable as important as knowing its central tendency? How is variation measured?

Accepted Answer

The answer of Why is knowing the variability or dispersion...

Question 11

A "codebook" is
A)only used in existing statistics research.
B)a document that tells the researcher where variables are located in the data file and what numbers go with what variable attributes.
C)the set of instructions that tell interviewers or experimenters how to treat respondents or subjects.
D)an unnecessary part of data analysis since computers were invented.
E)a sheet of paper with a grid of 80 columns corresponding to data card columns,with rows representing an individual card.

Accepted Answer

A codebook is a document that provides information about variables in a dataset, such as their names, labels, and coding schemes. It helps researchers understand the data and ensures uniformity in data analysis. Codebooks are widely used in social science research and are especially important in secondary data analysis where researchers use existing datasets.

Question 12

An elementary school teacher has three classes.She finds the following mean and standard deviations for student IQ scores.  She knows she is most effective when the students all have similar IQ levels.Which class is she likely to be most effective with?
A)Class #1
B)Class #2
C)Class #3
D)Classes #1 and #2 equally
E)Classes #1 and #3 equally

Accepted Answer

The answer of An elementary school teacher has three classes.She...

Question 13

You discover that the years of marriage before a divorce for nine whites and nine nonwhites are as follows: Whites 12,1,8,9,10,17,3,6,6
Non-Whites 1,9,15,18,11,13,14,7,3
Which statement about this data is true?
A)There is no difference in the range for the two groups.
B)The median years of marriage prior to divorce is three years longer for whites than nonwhites.
C)The mean years of marriage prior to divorce are the same for both groups.
D)On average,nonwhites stay married longer prior to divorce than whites.
E)The mode for the two groups is the same.

Accepted Answer

The mean and mode cannot be determined without additional information, and the range for nonwhites (18-1=17) is greater than the range for whites (17-1=16), so options A, B, and E are incorrect. However, the average number of years of marriage prior to divorce for nonwhites (10.6 years) is greater than the average for whites (8.3 years), so option D is correct.

Question 14

Which neighbourhood(s)has an income distribution resembling a normal curve?
A)Glenbrook
B)Meadowbrook
C)Elmbrook
D)Glenbrook and Elmbrook
E)Meadowbrook and Elmbrook

Accepted Answer

The answer of Which neighbourhood(s)has an income distribution resembling a...

Question 15

Calculate the median for the following six shoe sizes: 9,10,10,8,12,11.
A)8
B)8)5
C)9
D)9)5
E)10

Accepted Answer

The answer of Calculate the median for the following six...

Question 16

Explain how a researcher codes,enters,and cleans data so that it can be used for statistical analysis.What procedures are involved in each of these steps?

Accepted Answer

The answer of Explain how a researcher codes,enters,and cleans data...

Question 17

What are five measures of association that are useful when interpreting bivariate statistics? Describe each one and also specify which level of data each one is applicable to.

Accepted Answer

The answer of What are five measures of association that...

Question 18

Calculate the mode for the following six shoe sizes: 9,10,10,8,12,11.
A)8
B)8)5
C)9
D)9)5
E)10

Accepted Answer

The mode is the value that appears most frequently in the set. In this case, the shoe size that appears most frequently is 10, making E the correct choice. None of the other choices appear more than once in the set.

Question 19

Describe each of the three techniques researchers use when deciding whether a relationship exists between two variables.

Accepted Answer

The answer of Describe each of the three techniques researchers...

Question 20

Which neighbourhood(s)has the greatest differences in family income?
A)Glenbrook
B)Meadowbrook
C)Elmbrook
D)Glenbrook and Elmbrook
E)Meadowbrook and Elmbrook

Accepted Answer

The answer of Which neighbourhood(s)has the greatest differences in family...

Quiz 11: Analysis of Quantitative Data

Discuss the concepts of control variables and trivariate tables.What are three limitations of trivariate tables?

Is a Type I or Type II error more likely if a 0.05 level is used? Explain.

Describe each of the three measures of central tendency.What are the main differences between them? How are they affected by a normal versus a skewed distribution of data?

A researcher wants to express the middle of a distribution of numbers whereby half the cases are higher and half the cases are lower than the middle value.What statistical measure should the researcher use?

Calculate the mean for the following six shoe sizes: 9,10,10,8,12,11.

Describe four ways a researcher can display information about univariate statistics.

Which neighbourhood(s) has an income distribution resembling a skewed curve?

Describe,as simply as possible,what is meant by the statement "It is statistically significant at the 0.05 level."

What are two ways in which statistical relationships can be described? Provide an example for each one.

Why is knowing the variability or dispersion of a variable as important as knowing its central tendency? How is variation measured?

A "codebook" is

An elementary school teacher has three classes.She finds the following mean and standard deviations for student IQ scores. She knows she is most effective when the students all have similar IQ levels.Which class is she likely to be most effective with?

You discover that the years of marriage before a divorce for nine whites and nine nonwhites are as follows: Whites 12,1,8,9,10,17,3,6,6 Non-Whites 1,9,15,18,11,13,14,7,3 Which statement about this data is true?

Which neighbourhood(s) has an income distribution resembling a normal curve?

Calculate the median for the following six shoe sizes: 9,10,10,8,12,11.

Explain how a researcher codes,enters,and cleans data so that it can be used for statistical analysis.What procedures are involved in each of these steps?

What are five measures of association that are useful when interpreting bivariate statistics? Describe each one and also specify which level of data each one is applicable to.

Calculate the mode for the following six shoe sizes: 9,10,10,8,12,11.

Describe each of the three techniques researchers use when deciding whether a relationship exists between two variables.

Which neighbourhood(s) has the greatest differences in family income?