Quote for statistics questions
Homework Set #1 1. The National Crime Victimization Survey is described in Ch. 1 (p. 7). In 2015, it included a supplement to report on school-based crime among those enrolled in K-12 education in the U.S. I’ve provided a link to the actual survey here. For the following questions only, identify the level of measurement (ordinal, nominal, or interval- ratio). https://www.bjs.gov/content/pub/pdf/scs15_q.pdf Questions 1d, 7, 14a, 21b, 24, and 39 2. The frequency distributions below show frequencies of murder and non-negligent manslaughter in Colorado for selected years (1999 and 2016) by age of the victim. a. Complete both frequency distributions by calculating percentages, cumulative frequencies and cumulative percentages for each table. Murder and Non-Negligent Manslaughter by Age of Victim In Colorado 1999 frequency % Cum. Frequency Cumulative % Under 18 36 18-29 68 30-39 31 40-49 31 50-59 13 60 and older 8 TOTAL 187 2016 frequency % cum. Frequency cum % Under 18 15 18-29 67 30-39 43 40-49 25 50-59 26 60 and older 13 TOTAL 189 Source: Colorado Bureau of Investigation tabulation of UCR data. b. Construct (hand-drawn is OK) a bar chart to display the frequencies for each (not cumulative frequencies or percentages nor the total). You should refer to the Graphics section of Ch. 2 (beginning on p. 40), and make sure to label your axes, give your chart a descriptive title (Figure 1. TITLE), and note your source as I do above. You should NOT graph cumulative frequencies/percentages or totals c. Write a paragraph giving an overview of the comparison of the age distribution of victimization between the two years. https://www.bjs.gov/content/pub/pdf/scs15_q.pdf d. What do the total frequencies of homicides in Colorado in 1999 (187 homicides) and 2016 (189 homicides) suggest about the overall homicide rate? That is, do you think it has increased, decreased, or remained about the same given that Colorado’s population has increased substantially during this period? Explain your answer. 3. In Fall 2016, CU-Denver reported enrollment of international students on the downtown campus by country of origin, as shown in the crosstabulation below (only the largest countries are detailed here). Answer the following, and think carefully about the appropriate numbers in your denominators, in particular: Country of Citizenship Under- graduates Graduate Students TOTAL Saudi Arabia 114 49 163 China 247 97 344 Qatar 50 0 50 Republic of Korea 12 19 31 India 8 180 188 United Arab Emirates 42 1 43 All others 89 144 233 TOTAL 562 490 1052 a. Among all students from China, what proportion were undergraduate students? b. What percentage of all undergraduate international students were from Qatar? c. What proportion of all graduate students are from Saudi Arabia? d. What is the overall ratio of undergraduate students to graduate students among the international students enrolled at the university? You should reduce this to ? undergrad students for every 1 grad student. 4. See the linked list of violent crime rates and rankings by state for 2012 (this is in the assignment in Canvas), and answer the following questions. a. Why are these (and so many other crime statistics) expressed as rates instead of total numbers (frequencies)? b. Provide a one paragraph summary of these data comparing the crime rates and rankings of three of these states (your choice of states). Be careful! These data already express rates so you don’t need to know the populations of each state to calculate rates. Just compare three states in one well-formulated paragraph – you don’t need to calculate anything here, just provide a comparison. 5. Consider the following table of information on selected Denver neighborhoods, then answer the following questions: Neighborhood Total Population (estimated) 2015 reported offenses (January – November) Burglary Arson Drug/ Narcotics Violations Montclair 5456 64 2 15 Congress Park 10,235 52 2 15 Capitol Hill 14,708 57 0 208 Source: http://www.denvergov.org/police/PoliceDepartment/CrimeInformation/CrimeStatisticsMaps/ a. Comparing Montclair and Congress Park, which of the two neighborhoods had the higher drug/narcotics violation rate in 2015? Provide your calculations of each of these two neighborhood’s rate per 1000 in answering this question. b. Which of the three neighborhoods has the highest arson rate? Again, support your answer by calculating the arson rate for each neighborhood per 100,000. 6. The following fictitious responses have been collected for 10 respondents to the NCVS school supplement for several of the questions referenced in question #1. For each question noted across the top, calculate an appropriate measure of central tendency (and don’t just report the mode for each). Be careful – all of the possible responses are coded with numeric codes, but some are nominal or ordinal, not interval-ratio. Summarize your results in a paragraph. Respondent ID Q1d Q7 Q14a Q21b Q24 1 1 5 4 0 Not applicable 2 2 4 1 0 Not applicable 3 2 4 2 2 1 4 1 2 3 0 4 5 3 1 3 1 1 6 3 4 2 0 1 7 1 4 4 0 1 8 2 3 4 3 2 9 1 2 1 0 Not applicable 10 1 6 1 0 3 7. Per capita expenditures for police protection for several cities are reported below for 2010 and 2015. Compute a mean and standard deviation for each year, then compare each across this five-year period. City 2010 2015 A $180 $210 B $95 $110 C $87 $124 D $101 $131 E $52 $197 F $117 $200 G $115 $119 H $88 $87 I $85 $125 http://www.denvergov.org/police/PoliceDepartment/CrimeInformation/CrimeStatisticsMaps/tabid/441370/Default.aspx