Q8 Homework

Practice Homework -- Identify Dependent and Independent Variables, the data types, the statistical procedure, the theory and the Null Hypothesis

Homework -- The Null Hypothesis for differing Data-type combinations

The effect of additional police on crime

Is there a difference in number of victimizations between violent offenders and non-violent offenders?

In a study of inmates, do prior arrests affect the mean sentence length?

Is there a difference in the GRE scores between Criminal Justice students at UNG compared to the population of Criminal Justice students nationwide?

Is the “count of students” higher among traditional or non-traditional Criminal Justice students?

Is there a difference in mean number of arrests between Hispanics, African Americans, and Caucasians?

Will the “mean number of illegal immigrants” after a border tightening policy be less than before the policy was in effect?

Is there a difference in the political party affiliation” (republican or democrat) between males and females?

What LSAT score is a Law student who has an IQ of 156 predicted to attain?

Is there a difference in the mean Minnesota Multi-Phasic Personality Inventory (MMPI) score between military and civilians?

Is there is a difference in income between different ethnic groups: white and nonwhite police officers.

A researcher conducted a study on job satisfaction between two employers: Federal employees and city/state employees. He has heard that federal jobs are more desirable, so he devised a job satisfaction scale from 1 to 10, (1 = very satisfied, 10 = very dissatisfied), to ascertain if employer type made a difference in job satisfaction.

Who has more repeat offenses, inmates under age-40 or inmates age-40 and over?

A social worker theorizes that higher levels of parental education lessens the frequency of the child’s delinquency. She gathers data on “parental education” and “shoplifting frequency” of children.

It is commonly theorized that liberals donate more money to charity than do conservatives.

A social scientist believes that, because married adults have the potential for two incomes, they will have more disposable income than single adults.

A political scientist is asked to research landslide winners in political positions (Governors were surveyed), to discover if “popularity in elections” is related to job effectiveness. He gathers data on how many “votes” were received by both candidates in the 50 state elections over the past 3 years, and how many “executive actions” the winner took while in office.

Is whether you are happily married or not related to income level? A researcher asked 40 subjects to rate their “marriage happiness” (rated on a scale of 1 to 6, 1 being near divorce and 6 being blissful), and the couple’s yearly income.

A CJ major is trying to find out if the crime rate is higher in areas with one or two officer patrols. It is theorized that the “crime,” is higher in one-officer “patrols type.” She collects data from 35 districts.

Certain special interest groups have convinced many voters through a media campaign that ethnic minority couples typically have more children than Caucasian couples.

A Researcher wants to determine the relationship between television viewing and education.

A drug identification unit wants to determine the “reaction time in seconds” between amphetamine users and those on placebos.

Child misbehavior was studied between working mothers and stay-at-home mothers

A follow-up study was conducted to ascertain the difference in “GPA” between children that grew up at daycare facilities and those that grew up at home.

A study was conducted to test the theory that high levels of “crime” are associated with low levels of “income.”

Homework Answers -- The Null Hypothesis for differing Data-type combinations

Sample Problem:

1. Metric / Metric Independent variable -- Dependent variable = metric

Example: the effect of additional police on crime

Theory: Adding police to a neighborhood will affect the number of crimes (Police go up, crimes go down)

Null hypothesis: There is not a statistically significant relationship between the number of crimes reported and the number of police present.

(p. < .05), the relationship is significant. Reject the null.

Study type / test statistic: Relationship study / Pearson r statistic.

These are the three null hypotheses used with the foregoing study designs

1. The relationship null hypothesis (used with a metric-metric data-type combination)

2. The differences null hypothesis (used with a metric-nominal data-type combination)

3. The non-parametric null hypothesis (used with a nominal-nominal data-type combination)

Homework – Problems

From the list below, identify the data-type combination and choose the correct procedure based on the study design.

a. Pearson r, b. Bivariate regression, c. Independent sample t-test,

d. Paired-sample t-test, e. One-Sample t-test, f. One-way Chi-Square, g. Two-Way Chi-square

h. Analysis of Variance (ANOVA)

Example: Is there a difference in the dependent variable mean “number of victimizations” among inmates between violent offenders and non-violent offenders?

___Metric_ _Nominal_ _Independent Samples t-test

Dependent Variable Independent Variable Statistical Procedure

1. In a study of inmates, does the mean arrests effect the dependent variable mean sentence length?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

2. Is there a difference in the dependent variable “GRE scores” between Criminal Justice students at UNG compared to the population of Criminal Justice students nationwide?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

3. Is the dependent variable “count of students” higher among traditional or non-traditional Criminal Justice students?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

4. Is there a difference in the dependent variable “mean number of arrests” between Hispanics, African Americans, and Caucasians?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

5. Will the dependent variable “mean number of illegal immigrants” after a border tightening policy be less than before the policy was in effect?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

6. Is there a difference in the dependent variable “count in political party affiliation” (republican or democrat) between males and females?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

7. What “LSAT score” (dependent variable) is a Law student who has an IQ of 156 predicted to attain?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

8. Is there a difference in the dependent variable mean “Minnesota Multi-Phasic Personality Inventory (MMPI)” score between military and civilians?

____________ ____________ ________________________________

Dependent Variable Independent Variable Statistical Procedure

a. Pearson r, b. Bivariate regression, c. Independent sample t-test,

d. Paired-sample t-test, e. One-Sample t-test, f. One-way Chi-Square, g. Two-Way Chi-square

h. Analysis of Variance (ANOVA)

Answers

1. In a study of inmates, does the mean arrests effect the dependent variable mean sentence length?

Metric Metric _Pearson r_

Dependent Variable Independent Variable Statistical Procedure

2. Is there a difference in the dependent variable “GRE scores” between Criminal Justice students at UNG compared to the population of Criminal Justice students nationwide?

Metric Nominal (sample/population) _One-Sample t-test_

Dependent Variable Independent Variable Statistical Procedure

3. Is the dependent variable “count of students” higher among traditional or non-traditional Criminal Justice students?

Count Nominal _One-way Chi-square_

Dependent Variable Independent Variable Statistical Procedure

4. Is there a difference in the dependent variable “mean number of arrests” between Hispanics, African Americans, and Caucasians?

Metric Nominal Analysis of Variance_

Dependent Variable Independent Variable Statistical Procedure

5. Will the dependent variable “mean number of illegal immigrants” after a border tightening policy be less than before the policy was in effect?

Metric Nominal (Before and After) _Paired-Sample t-test_

Dependent Variable Independent Variable Statistical Procedure

6. Is there a difference in the dependent variable “count in political party affiliation” (republican or democrat) between males and females?

Nominal Nominal Two-Way Chi-Square_

Dependent Variable Independent Variable Statistical Procedure

7. What “LSAT score” (dependent variable) is a Law student who has an IQ of 156 predicted to attain?

Metric Metric _Bivariate Regression_

Dependent Variable Independent Variable Statistical Procedure

8. Is there a difference in the dependent variable mean “Minnesota Multi-Phasic Personality Inventory (MMPI)” score between military and civilians?

Metric Nominal _Independent-Sample t-test_

Dependent Variable Independent Variable Statistical Procedure