Make syre your follow directions and show work Write and test hypotheses t tests for dependent samples by hand and in excelMake conclusions about your research based on hypothesis testFor any math pro

Statistical Analysis in Criminal Justice Problem Set # 7

Name_________________________________________________________________

Purpose

In these problems, you will:

  • Write and test hypotheses t tests for dependent samples by hand and in excel

  • Make conclusions about your research based on hypothesis test

Instructions

Please answer the following on this page or on additional paper if needed. You must show all of your work to receive full credit for your answers.

  • For any math problem, your final answer must be enclosed in a box.

  • For any excel problem, follow the directions and upload with problem set

  • Your homework must be completed independently, or it is considered academic dishonesty

Problems


  1. You are interested in knowing whether training on implicit bias will decrease the number of use of force incidents that police departments experience. You take a sample of police departments and track their number of use of force incidents during the 30 days before the training and the 30 days after the training. Below are the results:


Before Training

After Training

21

15

11

16

15

76

55

24

20

91

100

21

20



Formulate a research hypothesis, a null hypothesis and test the null at the .01 level of significance by hand. Write a paragraph that outlines your hypothesis, your main findings, and what you conclude about your research.



  1. Perform this test (of data above) of the null using excel. You must upload your excel Workbook that has a sheet named Problem Set 7 where you input the above values and show your output. Using the output would you reject your null hypothesis? How do you know (be specific), and what would you conclude about your research?


3. What would the critical value of t be in question #1, if you tested the null at .05? Is it larger or smaller? Why?


4. You are interested in knowing if calls for domestic disputes increased in police beats in the week following the shelter in place order in Atlanta following the Covid-19 outbreak. You collect data from police beats the week before the shelter in place order and the week after. The data are collected from the same police beats. You test your null hypothesis at a .01 level of significance using excel. Below are your findings.


t-Test: Paired Two Sample for Means

 

Before

After

Mean

35.00

38.14

Variance

776.67

803.48

Observations

7.00

7.00

Pearson Correlation

0.98

Hypothesized Mean Difference

0.00

df

6.00

t Stat

-1.37

P(T<=t) one-tail

0.11

t Critical one-tail

3.14

P(T<=t) two-tail

0.22

t Critical two-tail

3.71

 


  1. Write a null and research hypothesis in symbols.

  1. What is the mean number of domestic dispute calls before the shelter in place order?

  1. What is the sample size? How do you know?

  1. Circle the t critical value that you would use to compare the calculated value of t to.

  1. Using the p value from the table, can you reject your null hypothesis? How do you do?

  1. Using the t critical value and t calculated value from the table, can you reject your null hypothesis? How do you do?