Use the information in
[link] to answer the following questions.
Find the 30
^{th} percentile, and interpret it in a complete sentence.
What is the probability that the age of a randomly selected smartphone user in the range 13 to 55+ is less than 27 years old.
Let
X = a smart phone user whose age is 13 to 55+.
X ~
N (36.9, 13.9)
To find the 30
^{th} percentile, find
k such that
P (
x <
k ) = 0.30.
invNorm(0.30, 36.9, 13.9) = 29.6 years
Thirty percent of smartphone users 13 to 55+ are at most 29.6 years and 70% are at least 29.6 years.
Find
P (
x <27)
normalcdf(0,27,36.9,13.9) = 0.2342
(Note that normalcdf(–10
^{99} ,27,36.9,13.9) = 0.2382. The two answers differ only by 0.0040.)
There are approximately one billion smartphone users in the world today. In the United States the ages 13 to 55+ of smartphone users approximately follow a normal distribution with approximate mean and standard deviation of 36.9 years and 13.9 years respectively. Using this information, answer the following questions (round answers to one decimal place).
Two thousand students took an exam. The scores on the exam have an approximate normal distribution with a mean
μ = 81 points and standard deviation
σ = 15 points.
Calculate the first- and third-quartile scores for this exam.
The middle 50% of the exam scores are between what two values?
A citrus farmer who grows mandarin oranges finds that the diameters of mandarin oranges harvested on his farm follow a normal distribution with a mean diameter of 5.85 cm and a standard deviation of 0.24 cm.
a. Find the probability that a randomly selected mandarin orange from this farm has a diameter larger than 6.0 cm. Sketch the graph.
you are working for a bank.The bank manager wants to know the mean waiting time for all customers who visit this bank. she has asked you to estimate this mean by taking a sample . Briefly explain how you will conduct this study. assume the data set on waiting times for 10 customers who visit a bank. Then estimate the population mean. choose your own confidence level.
how can we find the expectation of any function of X?
Jennifer
I've been using this app for some time now. I'm taking a stats class in college in spring and I still have no idea what's going on. I'm also 55 yrs old. Is there another app for people like me?
Tamala
Serious
Hamza
yes I am. it's been decades since I've been in school.
Tamala
who are u
zaheer
is there a private chat we can do
Tamala
hello
how can I get PDF of solutions introduction mathematical statistics ( fourth education)
who can help me
a box contains a few red and a few blue balls.one ball is drawn randomly find the probability of getting a red ball if we know that there are 30 red and 40 blue balls in the box
the following data represent the number of pop up advertisement received by 10 families during the past month.calculate the mean number of advertisement received by each family during month.43,37,35,30,41,23,33,31,16,21
43+37+35+30+41+23+33+31+16 divided by 10
=310/10
=31
Anuforo
=310/10
=31
Anuforo
the following data represent the number of pop up advertisement received by 10 families during the past month.calculate the mean number of advertisement received by each family during month.43,37,35,30,41,23,33,31,16,21
In a recent survey of nurses in Region II, it was found out that the average monthly net income of nurses is Php 8,048.25. Suppose a researcher wants to test this figure by taking a random sample of 158 nurses in Region II to determine whether the monthly income has changed. Supposed further that th
Suppose from the 1,000 freshmen that took the entrance examination, it was found out that the standard deviation was 10
a. How many students passed the test if the passing score is set 75?
b. What scores comprise the middle 95% of all scores?