Question
In: Statistics and Probability
Suppose you are interested in studying regional differences in crime. You take a random sample of 100...
Suppose you are interested in studying regional differences in crime. You take a random sample of 100 cities in the South, and find a mean crime rate of 55 with a sample varianceof 5.78. A sample of 100 cities in the North has a mean crime rate of 50 with a sample varianceof 6.72.
1. Construct a 95% confidence interval around the difference in crime rates between the population of Southern cities and the population of Northern cities.
2. Interpret, in words, the meaning of this interval.
3. Test the null hypothesis that the mean crime rate for the population of cities in the South is less than (or equal to) the mean crime rate for the population of cities in the North. Use a significance level of .01.
Solutions
orchestra answered 2 years agoRelated Solutions
Suppose you are interested in studying regional differences in crime. You take a random sample of 100...
Suppose you are interested in studying
regional differences in crime. You take a random sample
of 100 cities in the South, and find a mean crime rate of 55 with a
sample varianceof 5.78. A sample of 100 cities
in the North has a mean crime rate of 50 with a sample
varianceof 6.72.
1. Construct a
95% confidence interval around the difference in crime rates
between the population of Southern cities and the population of
Northern cities.
2. Interpret, in words, the
meaning...
Suppose you take a random sample of 30 individuals from a large population. For this sample,...
Suppose you take a random sample of 30 individuals from a large
population. For this sample, the sample mean is 4.2 and sample
variance is 49. You wish to estimate the unknown population mean
µ.
(a) Calculate a 90% confidence interval for µ.
(b) Calculate a 95% confidence interval for µ.
(c) Based on (a) and (b), comment on what happens to the width
of a confidence interval (increase/decrease) when you increase your
confidence level.
(d) Suppose your sample size...
Suppose we are interested in studying flight delays. We know that on average there are 100...
Suppose we are interested in studying flight delays. We know
that on average there are 100 delays in a month with a population
standard deviation of 238 delays. Suppose we take a sample of 30
flight delays from American airlines only and we find that the
average from that sample for that month is 306 delays. We are
interested in seeing if the number of flight delays are increasing.
What is the standard error?
What is the margin of error...
Suppose you take a sample of 50 random people with COVID-19 and find that 30 of...
Suppose you take a sample of 50 random people with COVID-19 and
find that 30 of them are asymptomatic (show no symptoms),
. Suppose you want to test FOR whether or not the
percent of individuals with COVID-19 who are asymptomatic is
greater than 50%.
What is the null and alternative hypotheses for this test?
What are the critical values for conducting the hypothesis test
at the 10%, 5%, and 1% significance levels?
What is the test statistic for the...
A sociologist is studying the prevalence of crime in one major city. In a sample of...
A sociologist is studying the prevalence of crime in one major
city. In a sample of 150 randomly selected residents, 54 say that
they have been victimized by a criminal. Based on this sample,
construct a 99% confidence interval for the proportion of all
residents in this city who have been victimized by a criminal. Then
complete the table below. Carry your intermediate computations to
at least three decimal places. Round your answers to two decimal
places. What is the...
. A sociologist is interested in studying the relationship between education and crime. She randomly selects...
. A sociologist is interested in studying the relationship
between education and crime. She randomly selects 312 people and
asks them their education level and whether or not they have ever
been convicted of a felony. Is there evidence that education level
and crime are dependent?
Education
Level
No Felony Conviction Felony
Conviction
Less than 9
years
89
10
9 years - 12
years
78
10
12 years - 16
years
59
6
16+
years
53
7
b. State the...
Suppose we are interested in the mean scores on an exam. A random sample of 36...
Suppose we are interested in the mean scores on an exam.
A random sample of 36 scores is taken and gives a sample mean
(sample mean score) of 68 (x̄ = 68). In this example, we have the
unusual knowledge that the population standard deviation is 3
points. Do not count on knowing the population parameters outside
of textbook examples.
Find a 90% confidence interval for the true (population)
mean of statistics exam scores.
You are studying the ages of people afflicted with acne. You collected a random sample of...
You are studying the ages of people afflicted with acne. You
collected a random sample of 49 people that have acne and recorded
their ages. Using this data, you find that the sample mean age is
18.2 years and sample standard deviation is 18.3 years. Assume that
the ages are normally distributed.
To find a 91% confidence interval for the ages of people with
acne, what z-value would you need to use?
From univariate to bivariate Suppose you are interested in studying the effect of education on wages....
From univariate to bivariate
Suppose you are interested in studying the effect of education
on wages.
You propose the following regression of annual salary on years
of education and work experience:
wage=β0 +
β1 educ + β2exper + u
where
wage = annual salary
educ = years of formal education
exper = work experience
u = error term
In a simple regression analysis with educ as the only
explanatory variable, the effects of other factors, such as exper,
are ....
Sample Selection Methods. You are interested in selecting a sample of 100 students on your campus...
Sample Selection Methods. You are interested in selecting a
sample of 100 students on your campus to participate in a survey of
the effects of coffee on students’ ability to comprehend material
from a faculty member’s lecture. You have decided to limit your
selection to business majors and have obtained a comprehensive list
(ranked in descending order based on grade point average) of all
business majors. This list is 22 pages long and contains the names
of 2,200 business majors....
ADVERTISEMENT
ADVERTISEMENT
Latest Questions
- What is your opinion on the use of AI technology? Is it necessary or is it...
- For this problem, carry at least four digits after the decimal in your calculations. Answers may...
- Why is it okay to speculate on Currency?
- What is the budgeting cycle and master budget? Why should companies use a master budget?
- please i need to have good answers and easy to understand This exercise refers to the...
- (1 point) Find y as a function of t if y′′+25y=0, y(0)=4,y′(0)=6. y= ?
- What are the six steps of hypothesis testing? What does it mean if we reject the...
ADVERTISEMENT