Monday

December 22, 2014

December 22, 2014

Number of results: 8,351

**math**

can someone please explain to me what happens to the mean and standard deviation of the distribution of sample means as the size of the sample decreases?
*February 11, 2013 by kacie*

**stats**

suppose a normal distribution has a true population mean of 18 and a true standard deviation of 2. what % of observations will be 18 or less, 18 or greater and in the range from 16 to 20?
*June 19, 2013 by dometrice*

**statistics**

What is the standard deviation of a $1 bet on any one particular number, e.g., 33, in the game of American roulette? Notice the payoff is 35:1 for this type of bet.
*September 2, 2014 by Justin*

**Math**

Find the standard deviation for the given data. Round your answer to one more decimal place than the original data. 15, 42, 53, 7, 9, 12, 14, 28, 47 A. 29.1 B. 16.6 C. 17.8 D. 15.8 is it C
*September 23, 2014 by Amy*

**Please help me with this Q**

Find the standard deviation for the given data. Round your answer to one more decimal place than the original data. 22, 29, 21, 24, 27, 28, 25, 36 A. 4.8 B. 4.2 C. 2.8 D. 1.6
*September 23, 2014 by Amy*

**satistics**

3.Give the mean for the mean column of the Worksheet. Is this estimate centered about the parameter of interest (the parameter of interest is the answer for the mean in question 2)? Mean 3.50 Standard deviation 1.317 4.Give the mean for the median column of the Worksheet. Is ...
*December 4, 2011 by charlene*

**Statistics**

A sample of n=20 has a mean of M = 40. If the standard deviation is s=5, would a score of X= 55 be considered an extreme value? Why or why not? I understand that the score in question is 3 standard deviations above the mean. But I thought that I would need to convert this to a...
*November 9, 2014 by Terri*

**statistics**

1.A magazine reported that 6% of Americans read the news paper while driving. 100 drivers are selected at random, find the probability that exactly 25 of them say they read the newspaper while driving.(normal binomial formula to solve) 2. A survey of 30 adults found that the ...
*February 13, 2013 by Asia*

**statistics**

The population standard deviation (σ) for a standardized achievement test that is normally distributed is 8. a.) Calculate the standard error of the mean if you draw a random sample of 50 test scores. Show your work for full credit . . . b.) Your sample mean is ...
*February 21, 2012 by PK*

**Statistics**

Here is one that I really would like to know if I have the right answers- In data from a sample of 400 cases, a variable has a 95% confidence interval of 54.3 to 54.7 find the following: Mean, standard deviation and standard error. I have come up with the following Mean 54.5 ...
*April 12, 2007 by Angel*

**math**

Find the standard deviation for the given data. Round your answer to one more decimal place than the original data. 10) {15, 13, 31, 42, 58, 78} A) 36.5 B) 534.3 C) 39.5 D) 23.1
*December 13, 2009 by Anonymous*

**paul**

A stock will provide a rate of return of either –20% or +28% . 1. If both possibilities are equally likely, calculate the expected return and standard deviation.
*April 23, 2010 by john*

**Chemsitry**

I just took my Chemistry midterm, and would like to know how to calculate my grade on the midterm with the curve. MEAN = 8.9 STANDARD DEVIATION = 2.9 MY SCORE = 7 Thank You!
*October 12, 2010 by Anonymous*

**Statistics**

As standard deviation increases, samples size _____________ to achieve a specified level of confidence. A. Increases B. Decreases C. Remains the same
*October 21, 2010 by Daniel*

**statistics**

Suppose you have a data set that is normal and with a mean of 78 and a standard deviation of 9. Within what range would you expect to fine 95% of the data?
*December 13, 2010 by Razz*

**statistics**

using a mean of 80 and a standard deviation of 12. a) what is the score that divides the distribution such that 99% of the area is below it. b) what are the scores that bound the middle 95% of the distribution
*February 19, 2011 by henrietta*

**statistics**

using a mean of 80 and a standard deviation of 12. a) what is the score that divides the distribution such that 99% of the area is below it. b) what are the scores that bound the middle 95% of the distribution
*February 19, 2011 by henrietta*

**Math**

Find the standard deviation for the given data. Round your answer to one or more decimal places than the original data. 3){15,13,31,42,58,78} A)534.3 B)23.1 C)36.5 D)39.5
*March 28, 2011 by anonymous*

**stats**

the distribution of IQscores forms a normal distribution with a mean of 100 and a standard deviation of 15. what is the proportion of the population that has an IQscore greater than 130?
*April 11, 2011 by Anonymous*

**statistics**

I need a good research question for my statistics project. I have to compare two to calculate the difference. variance/standard deviation etc.
*April 19, 2011 by Kimberly*

**math**

The mean time for running a mile is 450 se4conds with a standard deviation of 40 seconds. What time would you need to beat to be in the top 10%?
*April 23, 2011 by Sue*

**Statistics**

jenny is 5'10" tall. the heights of the girls in the school are approximately normally distributed with a mean of 5'5" and a standard deviation of 2.6". What is the percentile of jenny's height?
*May 5, 2011 by Confused*

**Statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
*July 27, 2011 by Tamara Wright*

**stats**

Start with x = 100 and add four x values to make a sample of five data such that the standard deviation of these data equals 0.
*August 13, 2011 by wiliam*

**Math**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
*October 3, 2011 by Katty*

**statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
*October 3, 2011 by Jenifer*

**Math**

Can someone please help me figure out the mean, standard deviation, raw score, and z-score of 27,3,4,16,0.. Any help is super appriciated.. thanks sooo much.
*October 3, 2011 by Mark*

**Stats**

Each of 2 players, independently, play a game 5 times, with each game having probability of success 0.40. What is the standard deviation of the sum of the games they win
*October 9, 2011 by Jay*

**Statistics**

Start with x = 100 and add four x values to make a sample of five data such that the standard deviation of these data equals 0
*October 12, 2011 by Jen*

**math**

A company manufactures calulatoirs in batches of 64 and ther is a 5% rate of defects. Find the standard deviation for the number of defects per batch
*October 24, 2011 by Tami*

**statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 20 to be 115 or more?
*November 25, 2011 by Anonymous*

**statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be115 or more?
*November 27, 2011 by Mile*

**statistics**

Start with x = 100 and add four x values to make a sample of five data such that the standard deviation of these data equals 0.
*January 13, 2012 by dream*

**statistics**

Start with x = 100 and add four x values to make a sample of five data such that the standard deviation of these data equals 0.
*January 24, 2012 by Anonymous*

**math(stats)**

sample of n=5 scores (8,0,7,5,5) make an estimate of the standard deviation by finding average distance of the smallest and largest distance from the mean
*January 24, 2012 by juan777*

**statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
*February 1, 2012 by Jay*

**statistics**

Suppose IQ scores have a bell-shaped distribution with a mean of 100 and a standard deviation of 15. What percentage of the scores are above 130?
*February 23, 2012 by Beth*

**statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
*March 25, 2012 by Lea Kellogg*

**Math Stats**

A random sample of 30 plants has a sample standard deviation of 3.4 days for maturity. A 95% confidence interval for the population variance is __ to __days.
*March 28, 2012 by Apryl*

**statistics**

Suppose that a given population of trees have an average height of 10.2 ft and a standard deviation of 1.3 ft. Find the proportion of the population with heights above 11.8 ft.
*May 3, 2012 by Erik*

**Statistics**

Assume that a population is normally distributed with a mean of 100 and a standard deviation of 15. Would it be unusual for the mean of a sample of 3 to be 115 or more? Why or why not?
*June 3, 2012 by Anonymous*

**math**

The average price of gasoline lately has been hovering lately at $3.80. What is the standard deviation if the probability that a gallon of gas costs less than $3.00 is 15%?
*April 3, 2013 by Evie*

**~ MATH **

The average price of gasoline lately has been hovering lately at $3.80. What is the standard deviation if the probability that a gallon of gas costs less than $3.00 is 15%?
*April 3, 2013 by Oliwia*

**Statistics**

The yearly returns of a stock are normally distributed with a mean of 5.1% and standard deviation of 2.7%. Find the probability of a yearly return being greater than 6%.
*April 24, 2013 by Rem*

**STAT**

The score on a test are normally distributed with a mean of 75 and a standard deviation of 6. If the professor wishes to give A’s to the top 4%, what would be the cutoff score be for A’s?
*October 12, 2013 by Jacky*

**statistics-PLEASE HELP quick**

I have less than 24 hours to find the binomial probability of P(20<x<23)= and P(x>23)= if n=30 p=.23 u=6.9 q=.77 and the standard deviation is 2.3 can someone please show me how to get the outcome they want?
*November 4, 2013 by Amy*

**Math**

The yearly returns of a stock are normally distributed with a mean of 5.1% and standard deviation of 2.7%. Find the probability of a yearly return being greater than 6%.
*April 15, 2014 by Nick*

**Statistics**

The scores for math test #3 were normally distributed. If 15 students had a mean score of 74.8% and a standard deviation of 7.57, how many students scored above an 85%?
*August 22, 2014 by Lisa*

**math/stats**

What is the standard deviation of a $1 bet on any one particular number, e.g., 33, in the game of American roulette? Notice the payoff is 35:1 for this type of bet.
*September 2, 2014 by Justin*

**psych 42 **

The mean (μ) of the scale is 55 and the standard deviation (σ) is 7. Assuming that the scores are normally distributed, what PERCENTAGE of the population scores are above 59?
*September 21, 2014 by johnny*

**Statistics-Help please??**

Given a mean of 25 and a standard deviation of 2.3, what is the z-score of a data value of 29? I don't understand the formula they gave me for the z-score, so I dunno where to start. /:
*October 8, 2014 by Ali*

**statistics**

The scores for math test #3 were normally distributed. If 15 students had a mean score of 74.8% and a standard deviation of 7.57, how many students scored above an 85%?
*December 10, 2014 by ann*

**statistics**

A police department reports that the probabilities that 0, 1, 2, and 3 burglaries will be reported in a given day are 0.50, 0.41, 0.05, and 0.04, respectively. Find the standard deviation for the probability distribution. Round answer to the nearest hundredth.
*August 28, 2007 by darius*

**statistics**

A police department reports that the probabilities that 0, 1, 2, and 3 burglaries will be reported in a given day are 0.50, 0.41, 0.05, and 0.04, respectively. Find the standard deviation for the probability distribution. Round answer to the nearest hundredth.
*August 29, 2007 by tang*

**stats math**

Suppose x is normally distributed with a mean of 130 and a standard deviation of 25. Twenty-six percent of the values are less than what value? 123.5 114 136 146
*July 18, 2010 by thara*

**statistics**

find the range,standard deviation, and variance for the following sample date: 98,2,53,61,15,87,63,63,91,29,96,79,93,40,5,62 *please show all calculations for confirmation. thank you very much. i just want to double myself. thank you.
*October 16, 2010 by please help in panic mode-mary*

**statistics**

Assume the IQ's of men and women can be described by a Normal model with a mean of 100 and a standard deviation of 15. For the first part: What percent of people do you expect to have IQ's over 120?
*February 8, 2011 by alexandra*

**Statistics**

I am trying to find out the cut off score for selecting 10% of applicants with a mean of 500 and a standard deviation of 100 assuming that the standadized test is normally distributed.
*March 21, 2011 by Sam*

**statistics**

The following data lists the average monthly snowfall for January in 15 cities around the US: 26 6 5 45 44 10 39 33 15 33 11 36 36 4 32 Find the mean, variance, and standard deviation. Please show all of your work.
*January 30, 2012 by Anonymous*

**statistics**

The following data lists the average monthly snowfall for January in 15 cities around the US: 20 9 35 46 44 17 32 25 30 14 28 14 9 15 20 Find the mean, variance, and standard deviation. Please show all of your work.
*January 30, 2012 by Tywania*

**statistics**

The following data lists the average monthly snowfall for January in 15 cities around the US: 38 0 47 32 42 31 40 47 35 43 36 17 36 8 1 Find the mean, variance, and standard deviation. Please show all of your work.
*November 18, 2012 by Huffette*

**Math**

A non normal population is determined to have a mean of 60 and a standard deviation of 4. Ninety six percent of all observed values will occur in what range? A.52.16-67.84 B.50-60 C.48-72 D.40-80 I think A am I correct?
*December 29, 2012 by Chrissy*

**Finite Math**

The purchases made by customers at a convenience store are normally distributed, with a mean of $5.50 and a standard deviation of $3.50. What is the probability that a randomly chosen customer makes a purchase between $2.00 and $9.00?
*March 9, 2014 by Tanisha *

**Stats**

the average placement test score of a sample of 64 students out of 1000 registered at a community college is 70 with a standard deviation of 15. Construct a confidence interval with a 5% chance of error.
*April 6, 2014 by D*

**Math**

The data shows the total number of employee medical leave days taken for on-the-job accidents in the first six months of the year: 16, 7, 23, 9, 25, 16. Find the standard deviation.
*October 25, 2014 by Anonymous*

**Hypothesis testing**

5 Part Question: 6 timed runs were made along route A with an average of 95 minutes and a standard deviation of 10.5 minutes. Route B had 8 test runs with an average of 93 minutes and a standard deviation of 5.2 minutes. Determine if there sufficient evidence that route B is ...
*April 2, 2010 by Moe*

**Prob ans stat**

Let x be a random variable that represents the length of time it takes a student to complete a take-home exam in Dr. Larson's psychology class. After interviewing many students, it was found that x has an approximately normal distribution with mean of 5.2 hours and standard ...
*July 29, 2011 by Hannah*

**math**

The lengths of what are considered "1 inch bolts are found to be normally distrubted with a mean of 1.001 inches and a standard deviation of 0.002 inches. If a bolt measures more than 2 standard deviations away from the mean, it is rejected for not meeting factory tolerances. ...
*April 12, 2011 by david*

**maths**

Please help with this question.The mean weight of the contents of samples of 30 bags of sugar has standard error 0.008kg.The mean is 1.0042kg.Standard deviation is 0.042kg Choose the option that is closest to the probability, to three decimal places, that the mean weight of ...
*June 5, 2011 by Rebecca*

**statistics/ please help ASAP**

a set of data is normally distributed with a mean of 500 and a standard deviation of 100. a) what would the standard score fora score of 700 be? b) what % of scores is between 500 and 700? c) what would the percentile rank for a score of 700 *please show and answer all ...
*October 28, 2010 by vedry frustrated please help and show work*

**Pre-calculus**

A set of data is normally distributed with a mean of 500 and a standard deviation of 40. What percent of the data is between 460 and 540? Answer: 68.3%
*October 8, 2008 by Lucy*

**stats**

How large a sample should be taken if the population mean is to be estimated with 99% confidence to within $72? The population has a standard deviation of $800 Please Help, im stuck
*November 17, 2008 by ks*

**Math**

If each score in a set of test scores is divided by 10, describe the effect of the division on the mean, median, mode, range, and standard deviation of the set.
*January 9, 2010 by Anna*

**Math & Data Management**

The height of baby tree are normally distributed with a mean of 31.5 cm and a standard deviation of 10 cm. What is the height above which 85% of the seedlings have grown?
*June 15, 2010 by Madmazel*

**Statistics**

IQ test scores are normally distributed with a mean of 97 and a standard deviation of 11.An individual's IQ score is found to be 123.Find the z-score corresponding to this value
*November 2, 2010 by Rachel*

**statistics**

Assuming the resting heart rates for a sample of individuals are normal distibuted with a mean of 70 and a standard deviation of 15. Waht percentage of rates less than 70
*November 12, 2010 by Darlene Watson*

**Statistics**

The weights of adult males are normally distributed with a mean of 172 lb and a standard deviation of 29 lb Q.Find the weight that divides the upper 2% of weights from the lower 98%
*March 10, 2011 by Nathan*

**Statistics**

Use the Empirical Rule to find what two values 95% of the data will fall between for a data set with a mean of 294 and standard deviation of 13.
*May 16, 2011 by Denise*

**statistics**

A 95% confidence interval for a population mean was reported to be 23,100 to 24,900. If the sample standard deviation is 5,808.26, what sample size was used in this study?
*June 5, 2011 by Anige*

**Help plz!! Math....**

Start with x = 100 and add four x values to make a sample of five data such that the standard deviation of these data equals 0
*October 12, 2011 by Jen*

**Stats**

Given the following frequency distribution, find the mean, variance, and standard deviation. Please show all of your work. Errors Frequency 51-53 9 54-56 19 57-59 16 60-62 24 63-65 25
*October 13, 2011 by Jennifer*

**Statistics**

a machine fills containers with a standard deviation of filling weights of 1.5. calculate the mean weight if only 4 % of the containers hold less than 19 ounces
*November 16, 2011 by Jerry*

**statisticas**

A 82% confidence interval for a sampling distribution with a mean of 100, a sample standard deviation of 24 and a sample size of 36 will be based on a á= ______ and a corresponding Zá of ____
*January 28, 2012 by Jason*

**Statistics**

A 82% confidence interval for a sampling distribution with a mean of 100, a sample standard deviation of 24 and a sample size of 36 will be based on a á= ______ and a corresponding Zá of ___
*March 5, 2012 by Jeff*

**Statistics**

A 82% confidence interval for a sampling distribution with a mean of 100, a sample standard deviation of 24 and a sample size of 36 will be based on a á= ______ and a corresponding Zá of ___
*March 5, 2012 by Jeff*

**statistics**

At the end of the festival the organizers estimated that a family of participants spent an average of $90.00 with a standard deviation of $15.00. What’s the probability that the mean amount spent will be NO more than $75?
*March 21, 2012 by Diane*

**Statics**

Given the following frequency distribution, find the mean, variance, and standard deviation. Please show all of your work. Class Frequency 61-63 19 64-66 17 67-69 5 70-72 10 73-75 12
*June 21, 2012 by kesha*

**Math**

Consider the following test scores obtained by a class. Test score 90 80 70 60 50 Frequency 1 4 11 6 2 Find the standard deviation (rounded to the nearest hundredth).
*December 4, 2012 by Debin*

**Statistics**

The amount of rainfall in January in a certain city is normally distributed with a mean of 4.2 inches and a standard deviation of 0.5 inches. Find the value of the quartile Q1
*April 21, 2013 by Sennie *

**statistics**

12 squirrels were found to have an average weight of 10.5 ounces with a sample standard deviation is 0.25. Find the 95% confidence interval of the true mean weight
*May 8, 2013 by Anonymous*

**help**

Assume that the salaries of elementary school teachers in the U.S. are normally distributed with a mean of $37,000 and standard deviation of $3500. The cutoff salary for teachers in the bottom 12% is
*October 13, 2013 by Anonymous*

**Statistics**

A population has a standard deviation of 15.2. How large a sample must be drawn so that a 95% confidence interval for the population mean will have a margin error equal to 3.5?
*March 26, 2014 by Nicole*

**math**

A population distribution is known to have standard deviation 20. Determine the p value of a test of the hypothesis that the population mean is equal to 50, if the average of a sample of 64 observations is a) 52.5 , b) 55.0 , c) 57.5
*August 20, 2014 by Rami*

**Statistics**

A study found that 8-to 12-year olds spend an average of $18.50 per trip to mall. If a sample of 49 children was used, find the 99% confidence inteval of the mean. Assume the standard deviation is $1.50.
*November 20, 2008 by Anonymous*

**MAth**

Scores of an IQ test have a bell shaped distribution with a mean of 100 and a standard deviation of 19. Use the empirical rule to determine the following. a.) What % of people has an IQ score between 81 and 119?
*July 17, 2012 by quita*

**statistics**

Working on "Inferences from Dependent Samples" trying to find the standard deviation of the difference data. Differences: 24, 53, 100, 40, -10,71,77,70, 39, 50 n=10 d=51.4 sd=??? (Answer suppose to be 30.8336 but not coming close to this number at all)
*November 30, 2012 by HELP*

**MATH**

Working on "Inferences from Dependent Samples" trying to find the standard deviation of the difference data. Differences: 24, 53, 100, 40, -10,71,77,70, 39, 50 n=10 d=51.4 sd=??? (Answer suppose to be 30.8336 but not coming close to this number at all)
*November 30, 2012 by Inferences from Dependent Samples*

**statistics**

Shoppers were asked how much money they were going to spend today in the mall. The mean dollars was $250 with a standard deviation of $15. In a group of 64 people, what is the probability that they spent less than $240?
*December 3, 2012 by Alley*

**Statistics**

Assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 15. Find the IQ score separating the top 37% from the others. Answer in one decimal place.
*March 28, 2014 by Tracy*

**Math**

The average hourly wage of employees of a certain company is $14.58. Assume the variable is normally distributed. If the standard deviation is $3.99, find the probability that a randomly selected employee earns less than $9.79.
*July 12, 2014 by Shelagh*

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