Question

In a survey of collage students, it was found that the amount of time spent on reading books per week was normally distributed with a mean of 32 minutes. Assume the distribution of weekly reading time follows the normal distribution with a population standard deviation of 2 minutes. Suppose we select a sample of 20 high school students.

1) What is the standard error of the mean time?

2)What percent of the sample means will be greater than 32.50 minutes?

3)What percent of the sample means will be greater than 31.50 minutes?

4)What percent of the sample means will be greater than 31.50 but less than 32.50 minutes?

Answer #1

In a recent survey of high school students, it was found that
the amount of time spent on reading books per week was normally
distributed with a mean of 28 minutes. Assume the distribution of
weekly reading time follows the normal distribution with a
population standard deviation of 2 minutes. Suppose we select a
sample of 16 high school students. What can we say about the shape
of the distribution of the sample mean time?
What can we say about...

Majesty Video Production Inc. wants the mean length of its
advertisements to be 32 seconds. Assume the distribution of ad
length follows the normal distribution with a population standard
deviation of 2 seconds. Suppose we select a sample of 20 ads
produced by Majesty.
What can we say about the shape of the distribution of the
sample mean time?
What is the standard error of the mean time? (Round your answer
to 2 decimal places.)
What percent of the sample...

in a recent survey of high school students it was
found that the average amount of money spent on entertainment each
week was normally distributed with a mean of $52.30 and a standard
deviation of$18.23. Assuming these values are represented of all
high school students, what is the probability that for a sample of
25, the average amount sent by each student exceeds $60?
a)0.3372
b)0.1628
c)0.4826
d)0.0174

In a survey, 91 college students were interviewed about how
much
time they spent on school e-mail each week. The sample average was
3.34 hours with a sample standard deviation of 7.728 hours.
Construct a 90% confidence interval for the population mean. Also,
find the margin of error. Round your answers to 3 decimal
places.
Группа выборов ответов
(1.994,4.686) margin of error=1.346
(1.994,4.686) margin of error=2.692
(1.731,4.949) margin of error=1.609
(1.731,4.949) margin of error=3.218
(1.994,4.686) margin of error=3.340

A survey was taken of 383 students that asked the question how
much time they spent watching television in a day (in minutes).
Suppose this sample study follows a Normal distribution with a
sample mean x-bar = 118 minutes. Also suppose the population has a
standard deviation σ = 53 minutes. Determine a 96% confidence
interval for the mean television watching time.
A. 112.67 to 123.31
B. 117.86 to 118.14
C. 112.44 to 123.56
D. 111.70 to 124.30

25 randomly selected students took a survey on how long they
spent on social media. The mean number of minutes these students
spent on social media was 205.1 minutes with a standard deviation
of 150 minutes.The population of the time spent on social media is
normally distributed. Construct a 98%confidence interval for the
population standard deviation of the time students spend on social
media.

The time spent watching TV per week by middle-school students
has a normal distribution with mean 20.5 hours and standard
deviation 5.5 hours.
(a) Find the percent who watch less than 25 hours per week
(b) Find the percent who watch over 30 hours per week

A group of statistics students decided to conduct a survey at
their university to find the average (mean) amount of time students
spent studying per week. Assuming a population standard deviation
of six hours, what is the required sample size if the error should
be less than a half hour with a 95% level of confidence?

According to a social media blog, time spent on a certain
social networking website has a mean of 24 minutes per visit.
Assume that time spent on the social networking site per visit is
normally distributed and that the standard deviation is 7
minutes.
a. If you select a random sample of 25 sessions, what is the
probability that the sample mean is between 23.5 and 24.5 minutes?
(Round to three decimal places as needed.)
b. If you select a...

According to a social media? blog, time spent on a certain
social networking website has a mean of 23 minutes per visit.
Assume that time spent on the social networking site per visit is
normally distributed and that the standard deviation is 4 minutes.
Complete parts? (a) through? (d) below. a. If you select a random
sample of 36 ?sessions, what is the probability that the sample
mean is between 22.5 and 23.5 ?minutes? nothing ?(Round to three
decimal places...

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