Question

1. A questionnaire of spending habits was given to a random sample of college students. Each student was asked to record and report the amount of money they spent on books and school supplies in a semester. The amount of money spent on books and school supplies is said to follow normal distribution. The sample of 85 students resulted in an average of $850.

a) What are the simple conditions necessary for the confidence interval to be valid?

b) Find and interpret a 96% confidence interval for the mean amount of money spent by college students on books and school supplies if the population standard deviation is $140.

Answer #1

a) The simple conditions necessary for the confidence interval to be valid are

i) Samples are independent

ii) Samples are taken from normal population

iii) Sample mean is follows Normal distribution

b)

A questionnaire about study habits was given to a random sample
of students taking a large introductory stats class. The sample of
35 students reported that they spent an average of 115 minutes per
week studying stats. Assume that the standard deviation is 40
minutes.
A) Give a 95% confidence interval for the mean time spent
studying stats by students in this class.
B) Is it true that 95% of the students in the class have weekly
studying times that...

In an simple random sample of 200 college students, 114 said
that they usually speed on interstate highways by 10 mph or more.
Give a 95% confidence interval for the corresponding proportion for
all college students. a: (0.5014,0.6455) b: (0.5431,0.6386) c:
(0.3567,0.4533) d: (0.5014,0.6386)

In a study about how much College students sleep at night, a
sample of 25 students was selected. The sample average mean number
of hours of sleep was 6.64 and the sample standard deviation was
1.075.
(a) Construct a 90% confidence interval for the true mean number
of hours of sleep at night College students get.
(b) Interpret the interval.
(c) What assumptions must be satisfied for the interval obtained
in part (a) to be statistically valid?

5) Suppose that simple random samples of college freshman are
selected from two universities, 25 students from school A and 20
students from school B. On a standardized test, the sample from
school A has an average score of 1010 with a standard deviation of
100. The sample from school B has an average score of 990 with a
standard deviation of 90.
a) What is the 90% confidence interval for the difference in
test scores at the two schools?...

Is college worth it? Among a simple random sample of 341
American adults who do not have a four-year college degree and are
not currently enrolled in school, 154 said they decided not to go
to college because they could not afford school.
1. Calculate a 95% confidence interval for the
proportion of Americans who decide to not go to college because
they cannot afford it, and interpret the interval in
context. Round to 4 decimal places.
(_,_)
2. Suppose...

Is college worth it? Among a simple random sample of 334
American adults who do not have a four-year college degree and are
not currently enrolled in school, 157 said they decided not to go
to college because they could not afford school. 1. Calculate a 90%
confidence interval for the proportion of Americans who decide to
not go to college because they cannot afford it, and interpret the
interval in context. Round to 4 decimal places. ( , )...

Is college worth it? Among a simple random
sample of 334 American adults who do not have a four-year college
degree and are not currently enrolled in school, 144 said they
decided not to go to college because they could not afford
school.
1. Calculate a 99% confidence interval for the proportion of
Americans who decide to not go to college because they cannot
afford it, and interpret the interval in context. Round to 4
decimal places.
( , )
2....

The Survey of Study Habits and Attitudes (SSHA) is a
psychological test that measures the motivation, attitude toward
school, and study habits of students. Scores range from 0 to 200. A
selective private college gives the SSHA to a simple random sample
of both male and female first-year students to study the difference
in mean attitudes towards school and study habits between men and
women. The data for men and women:
n
s
Men
20
121.3
32.85
Women
18
141.1...

Consider a sample of 30 college students from Victoria. Based on
this sample, it was found that the average amount spent on
beverages during the Halloween weeekend was $40. The population
standard deviation is $6.50. Assume the following: the population
of college students is very large relative to the sample size, and
the population is normally distributed.
What is the upper confidence limit for an 88% confidence interval
around the population mean?
Express your solution rounded to two decimal places.

In a random sample of 47 high-school students enrolled in SAT
test training, it was determined that the mean amount of money
spent per student was $110.96 per class with a sample standard
deviation of $8.30. Construct and interpret a 95% confidence
interval for the population mean amount spent per student for an
SAT class.
A) ($108.52, $113.40); We are 95% confident that the population
mean amount spent per student for a single SAT class is between
$108.52 and $113.40....

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 2 minutes ago

asked 22 minutes ago

asked 26 minutes ago

asked 30 minutes ago

asked 34 minutes ago

asked 40 minutes ago

asked 55 minutes ago

asked 58 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago