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May 4, 2016

Search: Standard Deviation-What?

Number of results: 9,508

Algebra
The mean is 18.1 the data set for 13 is -1.7 What is the standard deviation for this data set.
July 27, 2015 by Malu

statistics
The daily sales of a retail store are normally distributed with a standard deviation of $500. If the probability that sales will be less than $10,000 in any one day is 40%, what are the mean daily sales?
April 23, 2013 by Anonymous

Statistics
The daily sales of a retail store are normally distributed with a standard deviation of $500. If the probability that sales will be less than $10,000 in any one day is 40%, what are the mean daily sales?
April 22, 2015 by Anonymous

Statistics
ATM transaction times are normally distributed with a mean of 150 seconds and a standard deviation of 45 seconds. What is the probability a person takes less than 60 seconds to complete their transaction?
February 19, 2016 by Anonymous

stat
The ministry of transport and communication is responsible for the enforcement of airline safety regulations and has become concerned about an apparent increase in accidents and near mishaps involving commercial aircraft. One area of concern is overloading due to passenger ...
August 23, 2014 by LwEeNdO

Statistics
It is known that the amount of time needed to change the oil in a car is normally distributed with a standard deviation of 5 minutes. A random sample of 100 oil changes yielded a sample mean of 22 minutes. Compute the 99% confidence interval estimate of the mean of the ...
February 26, 2007 by Jason L

math
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.83 inch? (Give the answer to four decimal places.)
August 30, 2011 by Anonymous

Math
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.83 inch? (Give the answer to four decimal places.)
August 24, 2011 by Lee Ann

math
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.82 inch? (Give the answer to four decimal places.)
August 24, 2011 by apryl

alegbra
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.82 inch? (Give the answer to four decimal places.)
August 27, 2011 by apryl

people
Suppose that people's heights (in centimeters) are normally distributed, with a mean of 165 and a standard deviation of 6. We find the heights of 80 people. (a) How many would you expect to be between 159 and 171 cm tall?
December 11, 2011 by Anonymous

statistics
the life of electric bulbs has a normal distribution with a mean of 35 months and a standard deviation of 4 months. What should the warranty period be if the company that manufactures these bulbs does not want to replace more than 2% of the bulbs?
December 19, 2011 by HELPME

algebra
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.81 inch? (Give the answer to four decimal places.)
February 28, 2012 by Anonymous

stats
a sample of 16 atm transactions shows a mean transaction time of 67 seconds with a standard deviation of 12 seconds. State the hypotheses to test whether the mean transactiontime exceeds 60 seconds
February 29, 2012 by Anonymous

math
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.81 inch? (Give the answer to four decimal places.)
June 9, 2012 by Anonymous

staticstics
The average length of an adult blue whate is 30 meters with a standard deviation of 5.7 meters. If a sample of 31 whales is taken, what is the probability that their average lenght differs from the mean by more than 2.0 meters
October 17, 2012 by melinda

staticstics
The average length of an adult blue whate is 30 meters with a standard deviation of 5.7 meters. If a sample of 31 whales is taken, what is the probability that their average lenght differs from the mean by more than 2.0 meters
October 17, 2012 by melinda

statistics
All deal with a random variable X that follows a normal probability distribution with mean equal to 37 and a standard deviation of 5. Compute P(X < 39) Compute P(X < 29 or X > 41) Compute P(X > 30) Find the 42nd percentile for this distribution.
April 25, 2013 by luke

statistics
All deal with a random variable X that follows a normal probability distribution with mean equal to 37 and a standard deviation of 5. Compute P(X < 39) Compute P(X < 29 or X > 41) Compute P(X > 30) Find the 42nd percentile for this distribution.
April 25, 2013 by luke

statistics
if a toaster ovens hav an average life expectancy of 9.5 years with a standard deviation of 4.75 years. what is the probability that a toaster oven will last twenty years or will fail in one year or less?
September 21, 2013 by efe

Statistics
Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms. A. 45% of the student weights are above ____ kilograms? Z=.3264=x-75.5/10.3 Now what? I am lost! Please help me! Thanks!
February 10, 2014 by Anonymous

Statistics
Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms. A. 45% of the student weights are above ____ kilograms? Z=.3264=x-75.5/10.3 Now what? I am lost! Please help me! Thanks!
February 10, 2014 by Anonymous

statics
Walleye is a common game fish. Adult walleye have a length with a mean of 44 cm and a standard deviation of 4 cm and the distribution of lengths is approximately Normal. What fraction of walleye are longer than 52 cm in length?
June 22, 2015 by angel

statistics
Given a sample size of 36, with sample mean 400 and sample standard deviation 85, we perform the following hypothesis test, at the 95% level of confidence: Ho: = 450, Ha: 450. What is the question and what is the answer?
December 8, 2015 by Anonymous

statistics
You are designing a study to determine whether music has an effect on learning. Previous research indicates that the standard deviation to learn a task is 3.4 minutes. How many subjects would you need to ensure with 90% confidence that the estimate is within 1 minute of the ...
April 29, 2012 by tammy

FINANCIAL ACCOUNTING
A portfolio manager is managing a $10 million portfolio. Currently the portfolio is invested in the following manner: Investment Dollar Amount Invested Beta Electric Utility $2 million 0.6 Cable Company $3 million 0.8 Real Estate Development $3 million 1.2 International ...
November 15, 2012 by Yinka

Statistics
Suppose the mean height of a population is 65 inches with a standard deviation of 1.5 inches. What is the z value for a height (x) of 67 inches?
May 4, 2011 by Erik

math
Suppose the mean height of a population is 65 inches with a standard deviation of 1.5 inches. What is the z value for a height (x) of 67 inches?
October 25, 2011 by Daniela

statistics
Suppose the mean height of a population is 65 inches with a standard deviation of 1.5 inches. What is the z value for a height (x) of 67 inches?
May 15, 2012 by Anonymous

statistics
Suppose the mean height of a population is 65 inches with a standard deviation of 1.5 inches. What is the z value for a height (x) of 67 inches?
August 18, 2012 by deja

Statistics
Suppose the mean height of a population is 65 inches with a standard deviation of 1.5 inches. What is the z value for a height (x) of 67 inches?
November 1, 2012 by jassi

Statistics
For Mathguru_ from statistic question on Tuesday April 10, 2007 follow up question- what if I wasn't given the standard deviation either- how would I solve this problem Other tutors can help, but without the previous information, it is impossible to help you. Please repost ...
April 11, 2007 by Angel

Math
The Lifetimes of a certain brand of photographic light are normally distributed with the mean of 210 h and a standard deviation of 50 h. What percent of lights will need to be replaced within 233 h? Out of 2000 lights, how many will have a lifetime between 200 h and 400 h?
June 9, 2011 by Jerry

statistics
A researcher is interested in estimating the noise levels in decibels at area urban hospitals. She wants to be 95% confident that her estimate is correct. If the standard deviation is 4.02, how large a sample is needed to get the desired information to be accurate within 0.58 ...
September 2, 2011 by Laynette

Statistics
An automatic machine in a manufacturing process is operating properly if the lengths of an important subcomponent are independently and normally distributed with a mean of 120 cm and a standard deviation of 4.7 cm. Find the probability that if 3 are randomly selected, all 3 ...
September 21, 2011 by Meghan

statistics
Let's pretend the Work variable is normally distributed, with a mean/median/mode value of 22 and a standard deviation of 17. Based on these numbers, we can say that approximately 50 percent of SOC 390 students work more than ____ hours per week
November 4, 2011 by Sarah

statistics
LSAT test scores are normally distributed with a mean of 510 and a standard deviation of 110. Find the probability that a randomly chosen test-taker will score between 300 and 580. (Round your answer to four decimal places.)
November 21, 2012 by Anonymous

statistics
LSAT test scores are normally distributed with a mean of 490 and a standard deviation of 110. Find the probability that a randomly chosen test-taker will score between 320 and 600. (Round your answer to four decimal places.)
April 16, 2013 by jack

statistics
In a test of the effectiveness of garlic for lowering cholesterol, 44 subjects were treated with garic in a processed tablet form. Cholesorol levels were measured before and after the treament. the changes in their levels of LDL cholestorol (in mg/dL have a mean of 3.5 and a ...
March 1, 2015 by slomomo

Math
The percent of fat calories that a person in America consumes each day is normally distributed with a mean of about 36 and a standard deviation of about 10. Suppose that 16 individuals are randomly chosen. Is it appropriate to use the normal approximation for the sampling ...
November 20, 2015 by Brandy

Statistics
The lifetime of a 2-volt non-rechargeable battery in contant use has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. Ninety percent of all batteries have a lifetime less than ?
September 2, 2009 by Karen

Statistics
The lifetime of a 2-volt non-rechargeable battery in contant use has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. Ninety percent of all batteries have a lifetime less than ?
September 2, 2009 by Karen

statistics
Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,225 per hour and a standard deviation of $220. What is the operating cost for the lowest 5 percent of the airplanes?
November 21, 2010 by Barbara

Math - Data Management
I'm kinda stuck on my math homework, does anyone know how to do it? The results of a blood test at a medical lab are normally distributed with a mean of 60 and a standard deviation of 15. How low must a score be to lie in the lowest 5% of the results?
June 9, 2011 by Andy

statistics
the average starting salary is Rs 15000per month with a standard deviation of Rs.1000 assuming normal distribution,what is the probability that starting salary will be more than Rs.17000, out of 200 degree holders how many will getRs.14000?
August 7, 2011 by Anonymous

Statistics
Commuters were asked how many times a week they stop for coffee on their way to work. A survey found a mean of 3 times a week with a standard deviation of 0.55. Find the probability that the sum of 121 values is less than 350.
December 3, 2012 by Alley

statistics
A food snack manu. samples 15 bags of pretzels off the assembly line and weighed their contents. If the sample mean is 10.0 and the sample standard deviation is .15, find the 95% confidence interval estimate for the true mean.
January 3, 2013 by Kelly

Analytical Chemistry
The question: The pH of a solution is defined as pH = -log[H3O+]. If the pH of a solution is 3.72(+/- 0.03), what is the [H3O+] and its absolute standard deviation? Answer: How would I carry this out? I know to find the hydronium concentration wouldn't i just take e^3.72? How ...
January 28, 2013 by James

Statistics for Development
one hundred students seat for a mathematics examination.the scores from this examination are normaly distributed with a population mean of 65% and a standard deviation of (a=10).what is the probability that students score;(i)less than 75% (ii)at least85% (iii)between 60% and 75%
April 16, 2013 by Benson

statistics
The lifetime of a 2-volt non-rechargeable battery in constant use has a normal distribution with a mean of 516 hours and a standard deviation of 20 hours. Ninety percent of all batteries have a lifetime less than
May 31, 2013 by Anonymous

math 115
Let x be a continuous random variable that follows a normal distribution with a mean of 200 and a standard deviation 25. Find the value of x so that the area under the normal curve between and x is approximately 0.4798 and the value of x is greater than .
November 19, 2013 by louise

Statistics
Hello, my problem is I have a random sample of only 15 sales average is $115 with a known population standard deviation of $25.00. Obtain a 92% confidence interval and explain what your answer means. I am not sure what to do because the sample size is only 15. Thanks for your ...
November 29, 2013 by kim

statistics
The true highway mileage, Y, of a specific brand of hybrid vehicle has a normal distribution with a mean of 42 and a standard deviation of 1.5. Find the probability that a randomly selected hybrid vehicle gets more than 38 miles to the gallon.
June 17, 2014 by lisa

stats
Commuters were asked how many times a week they stop for coffee on their way to work. A survey found a mean of 3 times a week with a standard deviation of 0.55. Find the probability that the sum of 100 values is more than 290.
July 10, 2014 by brewster

math
Commuters were asked how many times a week they stop for coffee on their way to work. A survey found a mean of 3 times a week with a standard deviation of 0.55. Find the probability that the sum of 100 values is more than 290.
July 12, 2014 by brewser

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
October 1, 2014 by Anonymous

Statistics
Assume that the mean hourly cost to operate a commercial airplane follows the normal distribution with a mean of $2,325 per hour and a standard deviation of $240. What is the operating cost for the lowest 5 percent of the airplanes?
October 9, 2014 by Dany

7th grade math standard form scientific notation
In standard form: 5. 3.2 x 10^3 7. 4.1 x 10^8 9. Write the average weight of a blue whale, 2.6 x 10^5, in standard form. 15. 2.5 x 10^-3 17. 1.05 x 10^-2 19. Write the size of a grain of very fine sand, about 9.35 x 10^-3 cm, in standard form. Can somebody help? I have been ...
September 28, 2012 by Delilah

stat
the average number of pushups a United States Marine does daily is 300, with a standard deviation of 50. A random sample of 36 marines is selected. What is the probability that the sample mean is at most 320 push-ups? With a mean of 300, you are looking for a sample using a ...
April 15, 2007 by Anonymous

stats
A final exam in Math 160 has a mean of 73 with standard deviation 7.73. Assume that a random sample of 24 students is selected and the test score of the sample is computed. Assuming the scores are normally distributed, what percentage of sample means are less than 69?
January 23, 2012 by dan

Math (Algebra 1)
Consider the ages of 5 brothers: 32, 26, 28, 30, 28. Determine which of the following are true if a new brother is adopted at age 10. A) The median will decrease B) The mean will decrease C) The range will increase D) The standard deviation will decrease Please explain how you...
October 19, 2013 by Jordan

statistics
Answer the following. Show your work to get credit. Exam scores are normally distributed with a mean of 81 and a standard deviation of 9. a) What is the minimum score one must have to be in the top 4% of the students taking the exam? b) What percentage of scores are below 90? ...
October 13, 2014 by JAE

Statistics
In planning a family of 4 children assume boys and girls are equally likely on each birth. Find (i) the probability distribution (ii) the expected number of boys (iii) the standard deviation of the number of boys.
March 17, 2011 by Donald Crentsil

statistics
Assuming that the weights of newborn babies are normally distributed with mean 6.5 pounds and standard deviation 1.2 pounds, how many babies in a group of 80 do we expect to weigh more than 8.9 pounds? Please show work Thank you
June 28, 2011 by Harley

math
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.815 inch? (Give the answer to four decimal places.)
August 28, 2012 by Anonymous

math
The diameter of an electric cable is normally distributed, with a mean of 0.8 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.815 inch? (Give the answer to four decimal places.) 1 0
August 29, 2012 by Anonymous

math help
A random sample of size 26 is to be selected from a population that has a mean = 46 and a standard deviation of 15. (f) What is the probability that the sample mean will be within 6 units of the mean? (Give your answer correct to four decimal places.)
June 16, 2013 by Sue 6f

Math Statistics
Answer the following. Show your work to get credit. Exam scores are normally distributed with a mean of 81 and a standard deviation of 9. a) What is the minimum score one must have to be in the top 4% of the students taking the exam? b) What percentage of scores are below 90? ...
October 13, 2014 by JAE

Statistics
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
The weights of individual nails produced by the 'Hammer 'n Nail' hardware company follow a normal distribution with the average nail weight being 5.1 grams and the standard deviation in nail weight being 1.6 grams. When a nail is produced it is discarded if it weighs more than...
September 29, 2010 by GiNa

Stats
A random sample obtained from a population has a mean of =100 and a standard deviation of = 20. The error between the sample mean and the population mean for a sample of n = 16 is 5 points and the error between a sample men and population mean for a sample of n = 100 is 2 ...
November 11, 2014 by Michelle

Stats
A random sample obtained from a population has a mean of =100 and a standard deviation of = 20. The error between the sample mean and the population mean for a sample of n = 16 is 5 points and the error between a sample men and population mean for a sample of n = 100 is 2 ...
March 13, 2015 by Mark

BCIT
A series of standard solutions of benzene in toluene solvent is to be prepared for an internal standard procedure with ethylbenzene serving as the internal standard. Tell how you would prepare the solutions, including the milliliters of benzene concentrations are to be 0.5%, 1...
November 10, 2013 by lori

contemporary math
Intelligence quotients on the Stanford-Binet intelligence test are normally distributed with a mean of 100 and a standard deviation of 16. Use the 68-95-99.7 rule to find the percentage of people with the following IQs: a.) between 84 and 100 b.) below 52
June 23, 2008 by Alicia

Statistics
The Internal Revenue Service is studying contributions to charity. The mean calculated from a random sample of 36 returns is $150. Assume that the population standard deviation is known and equal to $20. Construct a 98 percent confidence interval for the population mean.
October 29, 2009 by Joshua

Stastics
Bank of Connecticut estimated that balance on credit cards have follows Normal Distribution mean $845 with standard deviation $270. Calculate probability that balance on a single credit card is greater than $750
March 7, 2010 by Mary

statistics
At a ski area in Vermont, the daytime high temperature is normally distributed during January, with a mean of 22F and a standard deviation of 10F. You are planning to snowboard there this January. What is the probability that you will encounter daytime highs of a) 42F or ...
April 23, 2010 by Rose

statistics
At a ski area in Vermont, the daytime high temperature is normally distributed during January, with a mean of 22F and a standard deviation of 10F. You are planning to snowboard there this January. What is the probability that you will encounter daytime highs of a) 42F or ...
April 29, 2010 by john

college
Suppose that, for a certain exam, a teacher grades on a curve. It is known that the grades follow a normal distribution with a mean of 70 and a standard deviation of 7. There are 45 students in the class. How many students should receive an A? Please, round your answer to the ...
December 22, 2010 by Anonymous

statistics
we are interested in testing at level of significance alpha =10 whether the population mean is different than 15. a random sample of size 25 is taken with a mean of 13.9. assume standard deviation is 2 and normally distributed population. find the values for zcrit
December 6, 2011 by jen

statistics
In a survey of 400 college students, 40 were left-handed. Treating the sample as if it were random and using 0.015 as the standard deviation of the sampling distribution of the sample proportion, what is the lower bound of a 95% confidence interval for the population proportion?
May 18, 2012 by D

statistics college
suppose we have a set of blood pressure set with a mean of 120 systolic and a sample standard deviation of 20 points assume a normal distribution of what two values should 95% of all systolic bp lie
May 22, 2012 by melba

Stat
The salaries at a corporation are normally distributed with an average salary of $29,000 and a standard deviation of $4,000. What is the probability that an employee will have a salary between $22,520 and $23,480? Enter your answer rounded to exactly 4 decimal places.
June 5, 2012 by Sam

statistics
A class test resulted in a mean score of 60% and a standard deviation of 15%. You scored 75%. Assuming the scores follow a normal distribution, and there are 200 in the class, how many students scored better than you? Give your answer to the nearest whole number.
August 30, 2012 by rebecca

statistics
The average homicide rate for the cities and towns in a state is 10 per 100,000 population with a standard deviation of 2. If the variable is normally distributed, what is the probability that a randomly selected town will have a homicide rate greater than 14?
March 24, 2013 by brittany

Statistics
A simple random sample of 10 households, the number of TV's that each household had is as follows: 1, 3, 1, 2, 0, 2, 1, 1, 1, 5 Assume that it is reasonable to believe that the population is approximately normal and the population standard deviation is 0.56. What is the lower ...
June 26, 2013 by Anonymous

Math/Statistics
A statistics teacher believes that the final exam grade for her elementary stats class have a normal distribution with a mean of 82 and a standard deviation on 8. Find the score which separates the top 10% of the scores from the lowest 90% of the scores.
August 11, 2013 by Sean

Statistics
The grades in the final exam of a random sample of 25 students produce a standard deviation, s = 9.5. a) Construct a 90% confidence interval estimate for the population variance, . b) Can we infer at 10% level of significance that the population variance is significantly ...
November 25, 2014 by Kendra

College of education ekiadolor Benin
The scores of an achievement test given to 100,000 students are normally distributed with mean 500 and standard deviation 100.what should the score of a student be to place him or her among the 10% of the students?
June 14, 2015 by Biriemi powei

Statistics
The distribution of heights of women aged 20 to 29 is approximately normal with a mean of 2.8 inches and standard deviation of 2.8 inches. The height (+/- 0.1 inch) of the middle 99.7% falls between a low of ?? inches and a high of ?? inches. Please help on how I set this up ...
September 10, 2015 by Angel

Stats
workers at a large toxic cleanup project are concerned that their white blood cell counts may have been reduced. The white blood cell count in the general population is known to have a mean of 7500 cells/mL with a standard deviation of 1750cells/mL a)what is the probability of...
May 23, 2015 by Ish

statistics
/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
given the group of numbers: 8,9,10,10,10,11,11,11,12,13. which of the following are the same? a)range and mean,b)mode and median, c)standard deviation and mode d)mean and median, e)none
April 22, 2011 by BV

Statistics
True or false? If the original x distribution has a relatively small standard deviation, the confidence interval for will be relatively short. Answer True False
July 7, 2012 by Desperate

Rioja
A normally distributed population with 200 elements has a mean of 60 and a standard deviation of 10. The probability that the mean of a sample of 25 elements taken from this population will be smaller than 56 is:
February 22, 2013 by Laws

statistics
A teacher finds that the test scores of a group of 40 students have a mean of 75 and a standard deviation of 10. If Anne has a test score of 88, what is Annes z-score?
November 14, 2013 by latisha

Probability/Statistics
Assume 20 oz. cola bottles are filled so that the mean amount of liquid contained in the bottle is 20 oz and the standard deviation is .12 oz. If a bottle is randomly selected, find the probability that the number of ounces in that bottle is greater than 20.21 oz.
June 21, 2008 by thomas

statistics
Bob is a salesman. He receives $20 for each sales plus a fixed salary of $100 per week. Bob's average weekly sales is 70 units with a standard deviation of 15. Bob works 45 weeks a year.
September 18, 2011 by tuyet

Statistics
If red has a probability of occurrence of .70 and black has a probability of occurrence of .30 and they are the only choices what is the probability that you pick the right color 10 out of 10 times and what is the standard deviation. I keep getting (.70*.50) + (.30*.50) = .50...
February 11, 2012 by Joe D.

statistics
Suppose the final exam scores in a large class is symmetric mound shaped with a mean of 70 points and standard deviation of 10 points. The percentage of students in the class who receive more than 60 points is approximately
February 17, 2012 by Anonymous

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