Suppose that a principal of a local high school tracks the number of minutes his students...
Suppose that a principal of a local high school tracks the number of minutes his students spend texting on a given school day. He finds that the distribution of minutes spent texting is roughly normal with a mean of 60 and a standard deviation of 20. Use this information to answer the question.
1. Based on the statistics, what is the probability of selecting at random a student who spends between 10 and 30 minutes texting?
Homework Answers
Solution :
Given that ,
mean = 
= 60
standard deviation = 
= 20
P(10< x < 30) = P[(10-60) /20 < (x - 
) / < (30-60) /20 )]
= P(-2.5 < Z <-1.5 )
= P(Z <-1.5 ) - P(Z < -2.5)
Using z table
= 0.0668-0.0062
probability= 0.0606
Add Answer to:
Suppose that a principal of a local high school tracks the
number of minutes his students...
Suppose a researcher believes that the average height of female students in a large local high...
Suppose a researcher believes that the average height of female
students in a large local high school is 140 cm. The researcher
wants to construct an interval that contains the true average
height of all female students in the local high school with a
certain prespecified probability. The researcher selects 36 female
students at random from the high school. The distribution of
heights is known to follow a normal distribution.
Suppose a researcher believes that the average height of female...
Students who take statistics courses have a normal distribution period of 55 minutes on average and...
Students who take statistics courses have a normal distribution period of 55 minutes on average and 15 minutes of standard deviation. Find the probability that any student spends 65-85 minutes on the exam.
The principal of a school claims that the percentage of students at his school that come...
The principal of a school claims that the percentage of students at his school that come from single-parent homes is 11%. He takes a random sample of 100 students and finds 15 students (15%) come from single-parent homes. At the 0.05 significance level, test his claim by providing each of the following: a. the null and alternative hypothesis b. the test statistic c. the pvalue d. state the final conclusion in nontechnical terms e. describe what type 1 error would...
A principal at a specific school thinks that his students are above average intelligence. He collects a random sample of...
A principal at a specific school thinks that his students are above average intelligence. He collects a random sample of IQ scores from 25 students from his school. His sample has a mean of 112. The mean population IQ is 100 with a standard deviation of 15. Does he have enough evidence to support his claim?
In order to investigate how many hours a day students at their school tend to spend...
In order to investigate how many hours a day students at their school tend to spend on course work outside of regularly scheduled class time, a statistics student takes a random sample of 150 students from their school by randomly choosing names from a list of all full-time students at their school that semester. The student finds that the average reported daily study hours among the 150 students is 2.23 hours. The standard deviation of the hours studied is 1.05...
in a recent survey of high school students, it was found that the amount of time...
in a recent survey of high school students, it was found that the amount of time spent on rading books per week, was normally distributed with a mean of 23 minutes. Assume the distribution of weekly reading time follows the normal distribution with a population standart deviation of 2 minutes. Suppose we select a sample of 11 high school students. A- What can we say about the shape of the distributiob of the sample mean time? ….. B- What is...
5. At a local high school 5000 juniors and seniors recently took an aptitude test. The...
5. At a local high school 5000 juniors and seniors recently took an aptitude test. The results of the exam were normally distributed with mean = 450 and = 50. Calculate the following: a. The PERCENT of students to the nearest tenth of a percent that scored over 425 b. The number of students that scored more than 475 C. The probability of a student selected at random having scored between 400 and 575 A statistics instructor recorded the grades...
5. At a local high school 5000 juniors and seniors recently took an aptitude test. The...
5. At a local high school 5000 juniors and seniors recently took an aptitude test. The results of the exam were normally distributed with mean = 450 and o = 50. Calculate the following: a. The PERCENT of students to the nearest tenth of a percent that scored over 425 b. The number of students that scored more than 475 C. The probability of a student selected at random having scored between 400 and 575 6. A statistics instructor recorded...
The average employee in the U.S.A. spends μ = 23 minutes commuting to work each day....
The average employee in the U.S.A. spends μ = 23 minutes commuting to work each day. Assume that the distribution of commute times is normal with a standard deviation of σ = 8 minutes. (a) What proportion of U.S. employees spend less than 15 minutes a day commuting? (b) What is the probability of randomly selecting an employee who spends more than 35 minutes commuting each day?
The scores of students on the SAT college entrance examinations at a certain high school had...
The scores of students on the SAT college entrance examinations at a certain high school had a normal distribution with mean μ=556.6 and standard deviation σ=27.7.(a) What is the probability that a single student randomly chosen from all those taking the test scores 562 or higher?For parts (b) through (d), consider a simple random sample (SRS) of 35 students who took the test.(b) What are the mean and standard deviation of the sample mean score x̅x̅, of 35 students?The mean...
Suppose a researcher believes that the average height of female
students in a large local high school is 140 cm. The researcher
wants to construct an interval that contains the true average
height of all female students in the local high school with a
certain prespecified probability. The researcher selects 36 female
students at random from the high school. The distribution of
heights is known to follow a normal distribution.
Suppose a researcher believes that the average height of female...
5. At a local high school 5000 juniors and seniors recently took an aptitude test. The results of the exam were normally distributed with mean = 450 and = 50. Calculate the following: a. The PERCENT of students to the nearest tenth of a percent that scored over 425 b. The number of students that scored more than 475 C. The probability of a student selected at random having scored between 400 and 575 A statistics instructor recorded the grades...
5. At a local high school 5000 juniors and seniors recently took an aptitude test. The results of the exam were normally distributed with mean = 450 and o = 50. Calculate the following: a. The PERCENT of students to the nearest tenth of a percent that scored over 425 b. The number of students that scored more than 475 C. The probability of a student selected at random having scored between 400 and 575 6. A statistics instructor recorded...
Most questions answered within 3 hours.
-
Where is the error in this code sequence?
String s1 = "Hello";
String s2 = "ello";...
asked 10 months ago -
Financial data for Joel de Paris, Inc., for last year
follow:
Joel de Paris, Inc.
Balance...
asked 10 months ago -
Consider this reaction:
Al2(SO4)3 (aq)+ BaCl3
(aq) Al2Cl6 (aq)- +
3BaSO4(s) . What is the...
asked 10 months ago -
Suppose that Savneet is considering increasing her
recent random sample from 20 car rentals to 40...
asked 10 months ago -
Trucks arrive at an unloading terminal at an average rate of 120
per hour.
Trucks arrive...
asked 10 months ago -
Why are methanol and ethanol completely soluble in water while
octanol is not very little soluble....
asked 10 months ago -
A facilities manager at a university reads in a research report
that the mean amount of...
asked 10 months ago -
When the CuSO4 is rehydrated by adding water to the anhydrous
compound, is this an endothermic...
asked 10 months ago -
A ray of sunlight is passing from diamond into crown glass; the
angle of incidence is...
asked 10 months ago -
A block of mass 0.249 kg is placed on top of a light, vertical
spring of...
asked 10 months ago -
how do the kidneys compensate in the presences of acidosis
a) trigger hyperventilate
b) reserve acid...
asked 10 months ago -
Question 501 pts
The rental rate of capital to the firm increases. Which of the
following...
asked 10 months ago