Question

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 lie in the interval you found in (A)? Explain

Answer #1

Sample size = n = 35

Sample mean = = 115

Population standard deviation = = 40

A) We have to construct 95% confidenc interval for the population mean.

Here population standard deviation is known so we have to use one sample z-confidence interval.

z confidence interval

Here E is a margin of error

Zc = 1.96 ( Using z table)

So confidence interval is ( 115 - 13.2520 , 115 + 13.2025) =
> **( 101.7480 , 128.2520)**

B)

Interpretation: We are 95% confidence that the population mean of the students in the class have weekly studying times that lie in the interval.

So given statement if **FALSE.**

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...

In a study of academic procrastination, the authors of a paper
reported that for a sample of 421 undergraduate students at a
midsize public university preparing for a final exam in an
introductory psychology course, the mean time spent studying for
the exam was 7.54 hours and the standard deviation of study times
was 3.40 hours. For purposes of this exercise, assume that it is
reasonable to regard this sample as representative of students
taking introductory psychology at this university....

In a study of academic procrastination, the authors of a paper
reported that for a sample of 411 undergraduate students at a
midsize public university preparing for a final exam in an
introductory psychology course, the mean time spent studying for
the exam was 7.44 hours and the standard deviation of study times
was 3.30 hours. For purposes of this exercise, assume that it is
reasonable to regard this sample as representative of students
taking introductory psychology at this university....

In a study of academic procrastination, the authors of a paper
reported that for a sample of 421 undergraduate students at a
midsize public university preparing for a final exam in an
introductory psychology course, the mean time spent studying for
the exam was 7.44 hours and the standard deviation of study times
was 3.30 hours. For purposes of this exercise, assume that it is
reasonable to regard this sample as representative of students
taking introductory psychology at this university....

A very large study of college students’ study habits found that
the time (in hours) that freshmen study each week is approximately
normal with mean 24 hours and standard deviation 8 hours. What is
the probability that a sample of size n equals 16 from this
population would result in a sample mean greater than 30 hours?
0.7734 0.2266 0.0013 0.9987

A class survey in a large class for first-year college students
asked, "About how many minutes do you study on a typical
weeknight?" The mean response of the 285 students was x⎯⎯⎯x¯ = 132
minutes. Suppose that we know that the study time follows a Normal
distribution with standard deviation σσ = 65 minutes in the
population of all first-year students at this university.
Use the survey result to give a 95% confidence interval for the
mean study time of...

Statistics professor has 115 students in a statistics class and
would like to estimate the number of hours each student studying
for the last exam. A random sample of 41 students was found to
study an average of 7.3 hours with a standard deviation of 1.9
hours. The 95% confidence interval to estimate the average number
of hours studying for the exam is

A sample of n = 36 students was taken for a study on study
habits at one small university. National studies have shown that
for all university students the mean number of hours studied per
week has population mean 11 hours and population standard deviation
3 hours.
Use the formulas from the CLT to give the mean and standard error
for the distribution of Xbar.

Average hours per week listening to the radio.
The Student Monitor surveys 1200 undergraduates from
four-year colleges and universities throughout the United States
semiannually to understand trends among college
students.12 Recently, the Student Monitor
reported that the average amount of time listening to the radio per
week was 11.5 hours. Of the 1200 students surveyed, 83% said that
they listened to the radio, so this collection of listening times
has around 204 (17% × 1200) zeros. Assume that the standard...

Problem 1 – Estimation of study hours
A random sample of 20 students drawn from a student population
in a very large public university. It is found that the 20 selected
students studied on average 16.4 hours per week outside class
contact time. Assume that study hours outside class contact time is
normally distributed. Also assume that the population standard
deviation on study hours outside class contact time is 5.5 hours
per week. Construct a 98 percent confidence interval for...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 17 minutes ago

asked 23 minutes ago

asked 47 minutes ago

asked 59 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 3 hours ago