Is the national crime rate really going down? Some sociologists say yes! They say that the reason for the decline in crime rates in the 1980s and 1990s is demographics. It seems that the population is aging, and older people commit fewer crimes. According to the FBI and the Justice Department, 70% of all arrests are of males aged 15 to 34 years†. Suppose you are a sociologist in Rock Springs, Wyoming, and a random sample of police files showed that of 37 arrests last month, 22 were of males aged 15 to 34 years. Use a 10% level of significance to test the claim that the population proportion of such arrests in Rock Springs is different from 70%.

Calculus For The Life Sciences
2nd Edition
ISBN:9780321964038
Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Chapter12: Probability
Section12.3: Conditional Probability; Independent Events; Bayes' Theorem
Problem 39E: The following problem submitted by Daniel Hahn of Blairstown, Iowa, appeared in the Ask Marilyn...
icon
Related questions
Topic Video
Question

Is the national crime rate really going down? Some sociologists say yes! They say that the reason for the decline in crime rates in the 1980s and 1990s is demographics. It seems that the population is aging, and older people commit fewer crimes. According to the FBI and the Justice Department, 70% of all arrests are of males aged 15 to 34 years†. Suppose you are a sociologist in Rock Springs, Wyoming, and a random sample of police files showed that of 37 arrests last month, 22 were of males aged 15 to 34 years. Use a 10% level of significance to test the claim that the population proportion of such arrests in Rock Springs is different from 70%.

(a) What is the level of significance?
State the null and alternate hypotheses.
O Ho: p<
< 0.7; H,: p = 0.7
Но: р+ 0.7; Hi:р%3D 0.7
О но: р 3D 0.7; H: р> 0.7
O Ho: p = 0.7; H,: p + 0.7
O Ho: p = 0.7; H, : p < 0.7
(b) What sampling distribution will you use?
The standard normal, since np > 5 and nq > 5.
The Student's t, since np > 5 and nq > 5.
The Student's t, since np < 5 and ng < 5.
The standard normal, since np < 5 and nq < 5.
What is the value of the sample test statistic? (Round your answer to two decimal places.)
(c) Find the P-value of the test statistic. (Round your answer to four decimal places.)
Transcribed Image Text:(a) What is the level of significance? State the null and alternate hypotheses. O Ho: p< < 0.7; H,: p = 0.7 Но: р+ 0.7; Hi:р%3D 0.7 О но: р 3D 0.7; H: р> 0.7 O Ho: p = 0.7; H,: p + 0.7 O Ho: p = 0.7; H, : p < 0.7 (b) What sampling distribution will you use? The standard normal, since np > 5 and nq > 5. The Student's t, since np > 5 and nq > 5. The Student's t, since np < 5 and ng < 5. The standard normal, since np < 5 and nq < 5. What is the value of the sample test statistic? (Round your answer to two decimal places.) (c) Find the P-value of the test statistic. (Round your answer to four decimal places.)
Sketch the sampling distribution and show the area corresponding to the P-value.
3
-2
-1
-2
-1
3
-2
-1
1
3
-3
-2
-1
1
2
3
WebAssign Plot
(d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level a?
At the a = 0.10 level, we reject the null hypothesis and conclude the data are statistically significant.
At the a = 0.10 level, we reject the null hypothesis and conclude the data are not statistically significant.
At the a = 0.10 level, we fail to reject the null hypothesis and conclude the data are statistically significant.
At the a = 0.10 level, we fail to reject the null hypothesis and conclude the data are not statistically significant.
(e) Interpret your conclusion in the context of the application.
There is sufficient evidence at the 0.10 level to conclude that the true proportion of arrests of males aged 15 to 34 in Rock Springs differs from 70%.
There is insufficient evidence at the 0.10 level to conclude that the true proportion of arrests of males aged 15 to 34 in Rock Springs differs from 70%.
3.
3.
Transcribed Image Text:Sketch the sampling distribution and show the area corresponding to the P-value. 3 -2 -1 -2 -1 3 -2 -1 1 3 -3 -2 -1 1 2 3 WebAssign Plot (d) Based on your answers in parts (a) to (c), will you reject or fail to reject the null hypothesis? Are the data statistically significant at level a? At the a = 0.10 level, we reject the null hypothesis and conclude the data are statistically significant. At the a = 0.10 level, we reject the null hypothesis and conclude the data are not statistically significant. At the a = 0.10 level, we fail to reject the null hypothesis and conclude the data are statistically significant. At the a = 0.10 level, we fail to reject the null hypothesis and conclude the data are not statistically significant. (e) Interpret your conclusion in the context of the application. There is sufficient evidence at the 0.10 level to conclude that the true proportion of arrests of males aged 15 to 34 in Rock Springs differs from 70%. There is insufficient evidence at the 0.10 level to conclude that the true proportion of arrests of males aged 15 to 34 in Rock Springs differs from 70%. 3. 3.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps with 1 images

Blurred answer
Knowledge Booster
Hypothesis Tests and Confidence Intervals for Proportions
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Calculus For The Life Sciences
Calculus For The Life Sciences
Calculus
ISBN:
9780321964038
Author:
GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.
Publisher:
Pearson Addison Wesley,
Holt Mcdougal Larson Pre-algebra: Student Edition…
Holt Mcdougal Larson Pre-algebra: Student Edition…
Algebra
ISBN:
9780547587776
Author:
HOLT MCDOUGAL
Publisher:
HOLT MCDOUGAL
Algebra & Trigonometry with Analytic Geometry
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage
College Algebra
College Algebra
Algebra
ISBN:
9781305115545
Author:
James Stewart, Lothar Redlin, Saleem Watson
Publisher:
Cengage Learning