Question

You want to study the average time per day spent on using mobile phones by students at an university. Your goal is to provide a 95% confidence interval estimate of the mean time per day. Previous studies suggest that the population standard deviation is about 4 hours per day. What sample size (at a minimum) should be used to ensure the the sample mean is within

(a) 1 hour of true population mean?

(b) 0.5 hour of true population mean?

Answer #1

Given that, population standard deviation = 4 hours

A 95% confidence level has significance level of 0.05 and critical value is,

We want to find, the sample size ( n ), for following margin of errors,

a) For margin of error ( E ) = 1 hour

Therefore, required sample size is **62**

b) For margin of error ( E ) = 0.5 hour

Therefore, required sample size is **246**

a university president, believes that the mean number of hours
per day all male students at the University use cell/mobile phones
exceeds the mean number of hours per day all female students at the
University use cell/mobile phones. To test the presidents belief,
you analyze data from 29 male students enrolled in a asa111 this
semester and 13 female students enrolled in asa111 this
semester.
b. Assuming equal population variances and the level of
significance equals 0.05, if the calculated...

Professor Kathaway believes that the mean number of hours per
day all male students at the University use cell/mobile phones
exceeds the mean number of hours per day all female students at the
University use cell/mobile phones. To test Professor Kathaway's
belief, you analyze data from 29 male students enrolled in
Management this semester and 13 female students enrolled in
Management this semester.
a. Assuming equal population variances, if the level of
significance equals 0.05 and the one-tail p-VALUE equals...

X believes that the mean number of hours per day all male
students at the University use cell/mobile phones exceeds the mean
number of hours per day all female students at the University use
cell/mobile phones. To test X’s belief, you analyze data from 29
male students enrolled in XXX 230 this semester and 13 female
students enrolled in XXX 230 this semester.
a. Assuming equal population variances, if the level of
significance equals 0.05 and the one-tail p-VALUE equals...

The mean number of hours of study time per week for a sample of
554 students is 22. If the margin of error for the population mean
with a 95% confidence interval is 2.1, construct a 95% confidence
interval for the mean number of hours of study time per week for
all students.

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.

A random sample of 90 UT business students revealed that on
average they spent 8 hours per week on Facebook. The population
standard deviation is assumed to be 2 hours per week.
If we want to develop a 95% confidence interval for the average
time spent per week on Facebook by all UT business students, the
margin of error of this interval is
The 95% confidence interval for the average time spent per week
on Facebook by all UT business...

A professor in the education department believes that a sample
of students study less hours per week when compared to the general
population of university students. The general population of
university students studies an average of 15 hours a week with a
standard deviation of 2. The professor randomly samples 16 students
and discovers her sample has a mean of 12. Use an alpha level of
0.05 to determine whether these students study less hours per week
when compared to...

a recent study of 25 students showed they spent average of
$18.53 on gas per week, the sample standard deviation of the sample
was $3.00, construct a 95% confidence interval for the mean amount
spent on gas per week

You want to estimate the proportion of full-time college
students who earn a bachelor’s degree in four years or less. How
large a sample would be needed to ensure a 95% confidence level
that the estimate is within 3 percentage points of the true
population proportion?

The technology committee at a college has stated that the
average time spent by students per lab visit has increased, and
the increase supports the need for increased lab fees. To
substantiate this claim, the committee randomly samples 12 student
lab visits and notes the amount of time spent using the computer.
The times are given in the accompanying table.
Time Mins: 79, 62, 56, 55, 66, 69, 67, 68, 134, 55, 9, 62.
The previous mean amount of time...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 1 minute ago

asked 1 minute ago

asked 29 minutes ago

asked 35 minutes ago

asked 35 minutes ago

asked 35 minutes ago

asked 37 minutes ago

asked 43 minutes ago

asked 47 minutes ago

asked 59 minutes ago

asked 1 hour ago

asked 1 hour ago