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May 24, 2015

Search: Standard Deviation-What?

Number of results: 8,781

STAT- important
What is the difference between normal distribution and approximate normally. Correct me if im wrong but I think the parameters of Normal is X~Normal (mu, standard deviation) but then approx. normal is X~Normal (mu, variation) im just really confused when you use each and such.
December 18, 2014 by Sarah

statistics
Assume the body weight of healthy fifth graders is normally distributed with a mean of 98.3 lbs and a standard deviation of 4.12 lbs. If you have a body weight of 89.3, what is your percentile score?
July 8, 2010 by Ab

Business Statistic
X f(x) 0 .25 1 .20 2 .15 3 .30 4 .10 Is it prpbsbility distribution valid? Explain and list the requirement for a valid probability distribution Calculate the expected value x Calulate the variance of x calculate the standard deviation of x
October 16, 2010 by Laverne

nba stats help!!
The weight of a product is normally distributed with a standard deviation of .8 ounces. What should the average weight be if the production manager wants no more than 1% of the products to weigh more than 7.3 ounces?
June 15, 2011 by jenny

Statistics
The actual weights of bag of pet food are normally distributed.The mean of the weights is 50.0 lb,with a standard deviation of 0.2 lb. A)About what percent of bags of pet food weigh less than 49.8 lb?
June 4, 2012 by Anonymous

STATISTICS
The height of PU men are normally distributed with mean 65 in. and standard deviation 5.3 in. find the probability of finding: a. A men selected is at least 75 in. tall? b. A man selected is no less than 58 in. tall?
September 30, 2012 by JOE

Statics
Assume that the population is normal. A sample of size 100 is taken. The resultant sample data has a mean of 48 and a standard deviation of 15. Construct the 99% confidence interval for the population mean.
December 2, 2012 by Heather

Statistics
A random sample of 60 riders waited in line a mean time of 42 minutes with standard deviation 12 minutes. Find a 90% confidence interval for the populationmean waiting time in line
March 21, 2013 by Lost37

Math
The inner diameter of a piston is normally distributed with mean of 10 cm and standard deviation 0.03cm a)below what value of inner diameter will fall fifteen percent of the piston rings?
April 7, 2013 by Kira

Statistics
he Oil Price Information Center reports the mean price per gallon of regular gasoline is $ 3.79 with a population standard deviation of $ 0.18. Assume a random sample of 40 gasoline stations is selected and their mean cost for regular gasoline is computed. 1. What is the ...
September 26, 2010 by John

basic statistics for the behavioral sciences
on a standard test of motor coordination, a sports psychologist found that the population of a average bowlers had a mean scores of 24,with a standard deviation of 6. she tested a random sample of 30 bowling alley and found a sample mean of 26, a second random sample of 30 ...
September 12, 2011 by jan

science
i need help with standard deviation and erro bars on graph, if i want to talk about my graph and mention the erro bars and what it means how do i do that?
April 16, 2010 by piper

statistics
the lenght of a species of fish is normally distributed with a mean of 24.3 inches and a standard deviation of 1.8 inches. What is the lenght that is exceeded by 30%of these fish
June 19, 2012 by Anonymous

prob and stats
–/3 points Notes Question: TanColM7 8.6.003. TKK Products manufactures electric light bulbs in the 50-, 60-, 75-, and 100-watt range. Laboratory tests show that the lives of these light bulbs are normally distributed with a mean of 774 hr and standard deviation of 68 hr. Find ...
October 15, 2010 by br0Ok3

Statistics
A telephone company receives 3 calls every minute on an average. If an operator has a watch that is not very accurate and which has a normal distribution with mean of 1 minute and standard deviation of 5 seconds, what is the probability that he measures 5 calls in a minute?
February 4, 2011 by Georgina Hughes

statistics
A study is discussed the purity of oxygen from a certain supplier. Assume that the mean was 99.61 with a standard deviation of 0.08. Assume that the distribution of purity was normal. Below what purity value would you expect to represent the smallest 25% of the population?
December 16, 2011 by shasha

Probability and Statistics
A marine biologist has determined that the weight of a full weight of 2000pounds and a standard deviation of 500 pounds. Determine the probability that the average weight of the next five sharks captured will be less than 2100lbs.
April 29, 2012 by Kim

Statistics
A random sample of customer incomes yields a mean income of $35000 with a standard deviation of $4500. Assume that the distribution of the incomes in normal. What income range would include 90% of the most popular incomes?
August 2, 2012 by Danielle

statistics
Suppose that the heights of female adults in the US are normally distributed with a mean (µ) of 65.4 inches and a standard deviation (σ) of 2.8 inches. Let X denote the height of a randomly chosen adult female. Find the probability that X is between 66 and 70 inches:
March 15, 2013 by Lori

Statistics
The age of customers for a particular retail store follows a normal distribution with a mean of 37.5 years and a standard deviation of7.6 years.What is the probability that the next customer who enters the store will be less than 42 years old?
January 3, 2015 by Leslie Meagan

Statistics
The Wechsler Adult Intelligence Scale (WAIS) is a common "IQ test" for adults. The distribution of WAIS scores for persons over 16 yrs of age is approximately Normal with mean (100) and Standard Deviation 15, (a) Whatis the probability that a random chosen individual has a ...
December 5, 2006 by Jason

math
The FunTime Amusement park customer load during the summer follows a normal distribution with mean 450 and standard deviation 80. Determine the probability that the number of customers on any given day during the summer will be less than 420.
September 29, 2009 by Matt

Math
Need help with word problem. In the life, inyears of a television set with a mean of 20 years and a standard deviation of 1.8 years, what should be the guarantee period if the sompany wants less than 1% of the tv sets to fail while under warranty? should I take the .1 - 20/1.8=
March 1, 2010 by Veronice

statistics
The typical amount of sleep per night for undergraduate college students has a bell shaped distribution with a mean of 7 and a standard deviation of 1.90 hours. Based on this distributional information we can conclude that at least 95 % of this population sleep ...
September 27, 2013 by jennifer

Algebra II
The grades on the last math exam had a mean of 88%. Assume the population of grades on math exams is known to be normally distributed with a standard deviation of 6. What percent of students earn a score between 72% and 90%? (5 points) 0.6255 0.5843 0.6754 0.5346
May 23, 2014 by Pewdiepie

Stat
Thirty randomly selected students took the calculus final. If the sample mean was 89 and the standard deviation was 6.2, construct a 99% confidence interval of the mean score of all students. Assume that the population has a normal distribution. what formula do i use????
September 30, 2014 by Billy

six sigma
If the mean value of the weight of a particular brand of dog food bag is 20.6 pounds and the standard deviation is 1.3, assume a normal distribution and calculate the percentage of bags that falls below the lower specification value of 19.7 pounds.
November 26, 2014 by stansler

math: 68-95-99.7 rule
suppose that prices of a certain model of new homes are normally distributed with a mean of $150,000 use the rule to find the percentage of buyers who paid: between $150,000if the standard deviation is $1200
April 30, 2015 by john

Stats
Find probability that a randomly selected TV will have replacement time less than 6 yrs. mean is 8.2 yrs standard deviation is 1.1 then provide warranty of 1% will be replaced what is the time length of the warranty
November 17, 2008 by Valerie

statistics
If 80% of the applicants are able to pass a driver's proficiency road test, find the mean, variance, and standard deviation of the number of people who pass the test in a sample of 300 applicants.
October 1, 2010 by jean

Statistics
the scores of a standardized test are normally distribution with a mean of 312 and a standard deviation of 68. The bottom 40% of scores are designed 'Need improvement'. What is the cutoff score for those who 'Need improvement'?
May 4, 2011 by Lauran

math
The weight of lolly pops in a box is normally distributed with a mean of 5kg and a standard deviation of 0.1kg. What is the probability that a randomly selected box of lolly pops weighs between 5.03 and 5.16 kg?
May 31, 2011 by TUVALU

statistics
FB: Attendance at a university's basketball games follows a Normal distribution with mean ě = 8,000 and standard deviation ó = 1,000. 60% of all games will have more than _______ people in attendance.
February 7, 2012 by Anonymous

STATISTICS
the percentage rates of home ownership for 8 randomdomly selected states are listed below. Estimate the population variance and standard deviation for the percentage rate of home ownership with 99% confidence. 66.0 75.8 70.9 73.9 63.4 68.5 73.3 65.9
April 17, 2013 by Paula

STATISTICS
the percentage rates of home ownership for 8 randomly selected states are listed below. Estimate the population variance and standard deviation for the percentage rate of home ownership with 99% confidence. 66.0 75.8 70.9 73.9 63.4 68.5 73.3 65.9
April 19, 2013 by Paula

statistics
Assume that body temperatures of healthy adults are normally distributed with a mean of 98.2°F and a standard deviation of 0.62°F. Find the 90th percentile of the sample mean body temperatures for samples of size 16.
May 7, 2013 by ali awan

statistics
Suppose that the average score on the GMAT exam is 500 and that the standard deviation of all scores is 100 points. You would expect approximately 95% of all GMAT scores to be between
July 24, 2013 by thomas

statistics
The scores for standardized test are normally distributed with a mean of 300 and standard deviation of 39. If the test is given to 700 students, how many are expected to have scores between 300 and 378.
July 25, 2013 by melissa

math
it is claimed that the average age of employees in a large company is 50. a sample of 36 employees is taken and the average age was 49. the standard deviation of the population was 5. use a level of significance of 0.5. what do you think of the claim?
July 30, 2013 by marissa

math
kris scored 630 points on a particular section of a CPA exam for which the score were normally distributed with a mean of 600 points and a standard deviation of 75 points. At a differenttime, kerry scored 540 points on the same section, for which scores were normally ...
April 12, 2011 by kaleb

math
kris scored 630 points on a particular section of a CPA exam for which the score were normally distributed with a mean of 600 points and a standard deviation of 75 points. At a differenttime, kerry scored 540 points on the same section, for which scores were normally ...
April 13, 2011 by shirley

finite math
kris scored 630 points on a particular section of a CPA exam for which the score were normally distributed with a mean of 600 points and a standard deviation of 75 points. At a differenttime, kerry scored 540 points on the same section, for which scores were normally ...
April 14, 2011 by margie

statistics
A psychologist interested in political behavior measured the square footage of the desks in the official office of four U.S. governors and of four chief executive officers (CEOs) of major U.S. corporations. The figures for the governors were 44, 36, 52, and 40 square feet. The...
June 29, 2009 by Gregory

statistics
5. Each year, a national achievement test is administered to 3rd graders. The test has a mean score of 100 and a standard deviation of 15. If Jane's z-score is 1.20, what was her score on the test?
September 2, 2011 by xiomara

statistics
Suppose that 30% of all telephone calls at work are for personal reasons. If a random sample of 15 is taken, let X be the number of personal calls. The standard deviation of the # of personal calls is:
June 5, 2013 by Anonymous

Statistics
For a population with a mean of µ=60 and standard deviation of Ợ=24, find the z=score corresponding to each of the following samples a. M=63 for sample of n=16 scores b. M=63 for sample of n=36 scores c. M=63 for sample of n=64 scores
December 13, 2013 by Lyndyc

Stats
A survey was conducted to determine the number of hours people listen to the radio. While most of the listening is in the car, it turns out that the mean is 2.5 hours with a standard deviation of 0.75 hours. Find the probability that the sum of 100 values is less than 240.
December 3, 2012 by Alley

statistics
The distribution of scores on a standardized aptitude test is approximately normal with a mean of 490 and a standard deviation of 95. What is the minimum score needed to be in the top 25% on this test? Carry your intermediate computations to at least four decimal places, and ...
May 6, 2012 by SHelia

statics
The times for completing one circuit of a bicycle course are normally distributed with a mean of 81.7 minutes and a standard deviation of 8.6 minutes. An association wants to sponsor a race and provide prizes for the top (that is, fastest) 15% of riders. Where should they ...
July 10, 2012 by john

math
The times for completing one circuit of a bicycle course are normally distributed with a mean of 81.7 minutes and a standard deviation of 8.6 minutes. An association wants to sponsor a race and provide prizes for the top (that is, fastest) 15% of riders. Where should they ...
July 12, 2012 by john

math
The times for completing one circuit of a bicycle course are normally distributed with a mean of 81.7 minutes and a standard deviation of 8.6 minutes. An association wants to sponsor a race and provide prizes for the top (that is, fastest) 15% of riders. Where should they ...
July 12, 2012 by john kay

Statics
In designing an experiment, a psychologist is willing to assume that the underlying distribution for the time to learn a list of words is approximately normal with a standard deviation of 40 seconds. He wants to be 95% sure that the maximum error of his estimate of the mean ...
December 1, 2012 by Heather

algebra
i need help: A national achievement test is administered annually to 9th graders. The test has a mean score of 100 and a standard deviation of 15. If John’s z-score is 1.20, what was his score on the test?
November 19, 2013 by mufasa

Statistics
A college admissions officer takes a simple random sample of 103 entering freshmen and computes their mean mathematics SAT score to be 493. Assume the population standard deviation is 112. What is the lower bound of the 99% confidence interval? Round your answer to the nearest...
June 26, 2013 by Please help me work out this problem!!!

statistics
Do you want to own your own candy store? Wow! With some interest in running your own business and a decent credit rating, you can probably get a bank loan on startup costs for franchises such as Candy Express, The Fudge Company, Karmel Corn, and Rocky Mountain Chocolate ...
November 5, 2012 by noell

stats
sample of n=64 scores is obtained from population with standard deviation =15 sample mean is 10 pts greater than the poulation mean what is zscore for sample mean
March 22, 2013 by tita

statistics
2. The results of a recent survey indicate that the average new car costs $23,000, with a standard deviation of $3,500. The price of cars is normally distributed. a. What is a Z score for a car with a price of $ 33,000?
September 11, 2010 by Anonymous

Phoenix of Arizona
If 80% of the applicants are able to pass a driver's proficiency road test, find the mean, variance, and standard deviation of the number of people who pass the test in a sample of 300 applicants.
February 17, 2012 by Jayda

statistics
Varsity team try out. Assume the distribution of heights to be normal w/a mean of 64inches & standard deviation of 4 inches. only 15 students passed. how many students joined the try out?
February 22, 2012 by mike

statistics
The life span of the battery pack is known to be Normally distributed with a mean of 250 hours and a standard deviation of 20 hours. How to find the percentage of the battery packs lasting more than 250 hrs.
May 6, 2012 by noe

statistics
The Intelligence Quotient (IQ) test scores for adults are normally distributed with a mean of 100 and a standard deviation of 15. What is the probability we could select a sample of 50 adults and find the mean of this sample is between 95 and 105?
November 11, 2012 by Trev

statistics
The winning team's score in 11 high school basketball games were recorded. If the sample mean is 9.5 points and sample standard deviation is 0.25 points, what is the 98% confidence interval for the true population mean?
November 24, 2012 by Christi

Steve help!
10,000 students took a math test. If there average score was 40 with standard deviation of 10, how many students must have scored between 20 and 40 marks? 3,772 2,227 5,000 3,334 4,772
November 28, 2012 by Tina

stats
scores on a university examination are normally distributed with a mean of 68 and standard deviation of 9. What percetnage of students scores above 77? The answer is 16% according to the professor that is correct. But I don't understand how the professor got to that answer.
March 14, 2013 by Anonymous

statistic
The random variable x represents the number of boys in a family with three children. Assuming that births of boys and girls are equally likely, find the mean and standard deviation for the random variable x.
August 20, 2013 by Kim

statistics
A random sample of 100 students from a high school was selected. If a 98% confidence interval estimate for the mean age of students is calculated to be 14.2511 to 14.9489, then the standard deviation of the sample mean is?
November 17, 2013 by zac

math
A study of 60 bolts of carpet showed that their average length was 180 yards. The standard deviation of the population is 6 yards. Which of the following is the 99% confidence interval for the mean length per bolt of carpet?
April 14, 2014 by hassan

math
Studies shown that gasoline use or compact cars sold in the U.S. is normally distributed, with a mean of 25.5 mpg and standard deviation of 4.5 mpg. Find the range of mileage for the middle 60% of compact cars.
November 18, 2014 by sarah

statistics
In a population of exam scores, a score of x=88 corresponds to z=+2.00 and a score of x=79 corresponds to z=-1.00. Find the mean and standard deviation for the population.
February 5, 2008 by Tegan

Math
In a population of exam scores, a score of X=88 corresponds to z= +2.00 and a score of X=79 corresponds to z= -1.00. Find the mean and standard deviation for the population.
September 25, 2009 by Jen

statistics
In a population of exam scores, a score of X=88 corresponds to z= +2.00 and a score of X=79 corresponds to z= -1.00. Find the mean and standard deviation for the population.
September 25, 2009 by Jen

AP Statistics
if the probability of a dribbling drummer is .38, find the standard deviation of the dribbling drummers drumming for the twelve drummers drumming
January 6, 2010 by Belle

statistics
In a population of exam scores, a score of X = 48 corresponds to z = +1.00 and a score of X = 36 corresponds to z = -0.50. Find the mean and standard deviation of the population.
March 17, 2010 by Teresa

Stats
A loaf of bread is normally distributed with a mean of 22 ounces and a standard deviation of .5 ounces. What is the probability that a loaf of bread is < 20.75
March 30, 2010 by Anonymous

statistics
In a population of exam scores,a score of X= 48 corresponds to z= 1 and a score of X= 36 corresponds to z= -.50. Find the mean and standard deviation for the population?
March 9, 2012 by Amy

Math
On a recent math exam, Alex received a score of 92%. His z-score is positive 2. If the mean for the exam is 84, what is the standard deviation?
April 16, 2013 by James Jones

Probability
A department store has determined that 25% of all their sales are credit sales. A random sample of 75 sales is selected and the proportion of credit sales in the sample is computed. a) What is the probability that the same proportion will be greater than 0.34? In a random ...
November 23, 2006 by Janice

Finite Math
If the life in years, of a television set is normally distributed with a mean of 46 years and a standard deviation of 4 years, what should be the guarantee period if the company wants less than 3% of the television sets to fail while under warranty?
February 13, 2010 by Maria

math
The heights in inches of 18 randomly selected adult males in LA are listed as: 70, 69, 72, 57, 70, 66, 69, 73, 80, 68, 71, 68, 72, 67, 58, 74, 81, 72. Display the data in a stem-and-leaf plot. 1. Find the mean. 2. Find the median. 3. Find the mode. 4. Find the range. 5. Find ...
May 19, 2010 by Bill

Statistics
The heights in inches of 14 randomly selected adult males in LA are listed as: 71, 67, 70, 59, 71, 68, 67, 71, 80, 68, 74, 69, 72, 68. 1. Display the data in a stem-and-leaf plot. 2. Find the mean. 3. Find the median. 4. Find the mode. 5. Find the range. 6. Find the variance...
September 20, 2010 by Shawna

Math: Statistics
A study of elephants wishes to determine the average weight of a certain subspecies of elephants. The standard deviation of the population is 2,014 pounds. How many elephants need to be weighed so we can be 93% confident to be accurate within 325 pounds?
November 17, 2010 by Anonymous

statistics
A company that manufacturers bookcases finds that the average time it takes an employee to build a bookcase is 23 hours with a standard deviation of 8 hours. A random sample of 64 employees is taken. What is the likelihood that the sample mean will be 18 hours or more?
March 6, 2012 by Diane

Math
For a class test, the mean score was 65, the median score was 71 and sthe standard deviation of the scores was 7. The teacher decided to add 5 points to each score due to a grading error. Which of the folloiwng must be true for thenew scores? TH
August 15, 2011 by Gail

statistics
The heights in inches of 14 randomly selected adult males in LA are listed as: 71, 67, 70, 59, 71, 68, 67, 71, 80, 68, 74, 69, 72, 68. 1. Display the data in a stem-and-leaf plot. 2. Find the mean. 3. Find the median. 4. Find the mode. 5. Find the range. 6. Find the variance. ...
November 13, 2011 by Anonymous

stats
blood cholesterol level of all men age 20-24 follows N(188,41) where the units for the men and standard deviation are in mg/dl. what is the probability that the sample mean takes a value between 185 and 191 if we sample 1000 men
October 12, 2012 by sam

statistics
A group of 49 randomly selected construction workers has a mean age of 22.4 years with a standard deviation of 3.8. According to a recent survey, the mean age should be mu=21.9. Test this hypothesis by constructing a 98% confidence interval for the population mean.
November 19, 2013 by Cheryl

statistics
the average act score submitted to a certain university is 26. to be eligible for admission, a student must score in the top 6% of applicants. if the scores are normally distributed with a standard deviation of 2.4, what is the minimum score needed to be considered for admission?
March 21, 2014 by roger

Statistics
The life of a blood pressure monitor has a normal distribution with an average of 40 years and a standard deviation of one year. What should the warranty be to replace a malfunctioning monitor with - if the company does not want to replace more than 1% of all the monitor. ...
June 6, 2014 by Ann

Math
The weekly salaries of 100 recent graduates of a private women's college are normally distributed with a mean of $600 and a standard deviation of $80. Determine the interval about the sample mean that has a 1% level of confidence. Use t=2.58 I don't know. 600/sqrt100 60 80+-2....
October 1, 2008 by Anonymous

Math
The weekly salaries of 100 recent graduates of a private women's college are normally distributed with a mean of $600 and a standard deviation of $80. Determine the interval about the sample mean that has a 1% level of confidence. Use t=2.58 I don't know. 600/sqrt100 60 80+-2....
October 1, 2008 by Anonymous

Statistics
The amount of fill(weight of contents)put into a glass jar of spaghetti sauce is normally distributed with mean=850g and standard deviation=8g.the probability that a random sample of 24 jars has a mean weight greater than 848g is?need help
March 23, 2011 by Joel

stats ( please check)
6. X has a normal distribution with a mean of 80.0 and a standard deviation of 3.5. Find the following probabilities: (A) P(x < 77.0) (B) P(75.0 < x < 85.0) (C) P(x > 85.0) (Points : 6) I think I have the first two but I am stumped on the third one. Thank you for ...
July 24, 2011 by Celest

statistics
In a preliminary study, the sample standard deviation for the duration of a particular back pain suffered by patients was 18.0 months. How large a random sample is needed to construct a 90% confidence interval so that an estimate can be made within 2 months of the actual duratio
August 2, 2011 by joe

statistics
The SAT scores of a certain population of students are approximatley normally distributed with a mean and standard deviation of 1000 and 200 points, respectively. the probabilalty that a student selected at random from the population has an SAT score between 800 and 1200 is?
February 28, 2013 by ken

math
A sample of size 100 is chosen from a normally distributed mean,(µ) and standard deviation 60. A researcher has made the statement as follow to conclude that value of µ: " reject H0:µ= 80 and accept H1: µ < 80. if x̅ < 68 " a) if the significant level used is ∝...
October 17, 2013 by sree

CRJ303-Statistics question
Re-worded from the "Study Questions" part of Chapter 5 from this site: "Student Study Site for Essentials of Social Statistics for a Diverse Society" Please show the steps for each question "When the Scholastic Aptitude Test (SAT) - now known as the Scholastic Assessment Test...
December 7, 2012 by Michael

statistics
14.how would you describe this set of data? In other words, how would you describe the “average” score (mean, median or mode and why)? How would you describe the variability (range, standard deviation, or both, and why)? 3 3 3 4 3 2 4 2 3 4
November 23, 2010 by Lola

Math
*Sigh* Can someone explain to me how I would work thru this problem? An honest coin tossed n=3600 times. Let the random variable Y denote the number of tails tossed. (a) find the mean and the standard deviation of the distribution of the random variable Y (b) what are the ...
October 5, 2006 by SherylA

statistics
The average price for new mobile homes is known to be distributed with a standard deviation of 350. if a random sample of 49 homes resulted in a sample mean of 38500, obtain a 90% confidence interval on the population mean.
March 26, 2009 by April

statistics
Assume that blood pressure readings are normally distributed with a mean of 123 and a standard deviation of 9.6. If 144 people are randomly selected, find the probability that their mean blood pressure will be less than 125
November 8, 2011 by Anonymous

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