Sunday

May 24, 2015

May 24, 2015

Number of results: 8,781

**math**

Consider the probability function. (Give your answers exactly.) P(x) = 5 − x 10 , for x = 1, 2, 3, 4 (a) Find the mean. (b) Find the standard deviation.
*May 29, 2013 by Tom*

**statistics**

Given a population of scores is normally distributed with mu of 110 and a standard deviation of 8 the percentage of scores that are below a score of 99?
*June 6, 2013 by Debra*

**statistics**

A sample of n = 25 scores has M = 20 and s2 = 9. What is the sample standard deviation? a. 3 b. 4.5 c. 9 d. 81
*December 26, 2013 by Lyn*

**Statistics **

Some IQ scores are standardized with a mean of 100 and a standard deviation of 16. Using the 68-95-99.7 Rule, Determine: What percent of people would have an IQ score above 116.
*February 25, 2008 by Math help*

**Statistics **

Some IQ scores are standardized with a mean of 100 and a standard deviation of 16. Using the 68-95-99.7 Rule, Determine: What percent of people would have an IQ score of at least 132.
*February 25, 2008 by Math help*

**algebra 1**

Which statistical method best represents this set of data? 1,2,5,2,3,7,300,5,3,3 a.mean b.median c.mode d.standard deviation I'm pretty sure it's B or C, but they are both the same number.
*September 21, 2010 by Lily*

**stats**

Some IQ tests are standardized to a Normal model with a mean of 100 and a standard deviation of 16. About what percent of people should have IQ scores above 116?
*September 26, 2010 by Jamie*

**Maths**

5. Compute the two regression equations on the basis of the following data: X Y Mean 40 45 Standard Deviation 10 9 Given that the coefficient of correlation between X & Y is 0.50. Also estimate the value of Y for X=48?
*October 9, 2010 by Neeraj Bhanot*

**Trig. Math**

The mean score on a normally distributed exam is 42 with a standard deviation of 12.1. Which socre would be expected to occur less than 5% of the time? 1) 25 2) 32 3) 60 4) 67 -I know the answer is 67, but i dont know why .. PLEASE help!
*January 20, 2011 by Tami*

**stats**

We are interested in customer satisfaction ratings for a particular video game. In a group of 65 customers, we nd a sample mean of 42.95 and the standard deviation is 2.64. Find a 95% Con dence interval for u.
*July 31, 2011 by michelle*

**statistics**

a teacher decides to fail 25% of the class.Examination marks are roughly normally distributed w/a mean of 72 & standard deviation of 6. what mark must a student make to pass?
*February 22, 2012 by mike*

**statistics**

The scores on a national achievement test are normally distributed with a mean of 50 and a standard deviation of 10. Out of a group of 200 students, how many would you expect to score more than 70?
*March 20, 2012 by Anonymous*

**Statistics**

team members estimated that a group of participants spent an average of $90.00 with a standard deviation of $15.00. What is the maximum amount that you can spend and still be in the lowest 20%? and the minimum that you need to be in the highest 15%?
*March 23, 2012 by Diane*

**calculus**

a random sample of 80 students at a large school shows an average grade of 72 in algebra with a standard deviation of 4. find the t-score you would use for an 95 % confidence interval
*November 27, 2012 by emanuel hargrove*

**Statistics**

assume that adults have IQ scores that are normally distributed with a mean of 105 and a standard deviation of 15 find the probability that a randomly selected adult has an IQ between 89 and 121 ?
*December 12, 2012 by Rebecca*

**stats**

The amount that airlines speed on food per passenger is normally distributed with means $8.00 and standard deviation $2.00. What is the probability that a randomly selected airline spends more than $12.50?
*March 17, 2013 by chris*

**statistics**

The amount that airlines speed on food per passenger is normally distributed with means $8.00 and standard deviation $2.00. What is the probability that a randomly selected airline spends more than $12.50?
*March 17, 2013 by tony*

**stats.**

The amount that airlines spend on food per passenger is normally distributed with mean $8.00 and standard deviation $2.00. What is the probability that a randomly selected airline spends more than $12.50.
*April 2, 2013 by chris*

**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?
*July 7, 2013 by Laurin*

**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?
*July 7, 2013 by Laurin*

**statistics**

In a distribution of sentence lengths in months like the following: 6, 12, 10, 18, 24, 360; which statistic would a researcher not want to report? a. standard deviation b. mean c. range d. raw numbers
*November 29, 2013 by Jim*

**statistics, math, college**

assume that adults have I.Q scores that are normally distributed with a mean of 100 and a standard deviation 15. find p2 which is the IQ score seperating bottom 2% from the top 98%
*February 11, 2014 by andrea*

**Math**

a random sample of 28 patients across the country had an average cost of 5250 with a standard deviation of 629.at a= 0.025 can it be concluded that the mean is less than 5400
*April 27, 2014 by Anonymous*

**Prob&Stat**

If 52% of the customers at a certain grocery store regularly use coupons, what is the approximate standard deviation of the sampling distribution of the proportion for samples of size 240? 2.1% 3.2% 4.7% 10.4%
*December 14, 2014 by Bailey*

**Statistics**

Among the population of criminal justice students, the average score on the final exam was 74, with a standard deviation of 11.6. What is the probability of randomly selecting a student who earned an A (90 or better)?
*February 27, 2015 by Maddie *

**statistics**

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.
*November 18, 2008 by Kennon*

**Stats**

Test the claim that the mean body temperature is less than 98.6 using a= 0.05. Assume a smaple of 16 yilded a mean of 98.2 with a standard deviation of 0.6
*April 1, 2009 by Sue*

**Stats help**

Test the claim that the mean body temperature is less than 98.6 using a=0.05. assume a sample of 16 yielded a mean of 98.2 with a standard deviation of 0.6
*April 1, 2009 by Sam*

**stats**

A club has 50 members. If there is a 10% absentee rate per meeting, find mean and standard deviation: How do you do the problem step by step
*April 16, 2009 by ce*

**Math**

A normal distribution has a mean of 20 and a standard deviation of 3.What is the probability that a randomly selected x-value from the distribution is: A)at least 14? B)at most 26? C)Between 8 and 23?
*December 13, 2009 by Sam*

**Statistics**

The mean IQ among members of a club is 118 with a standard deviation of 9.46. What percentage of the members had IQ scores of 115 or higher?
*April 28, 2010 by CJ*

**Statistics**

The population standard deviation is estimated to be $300. If a 98% confidence interval is used and an interval of +/-$75 is desired, how many cardholders should be sampled?
*July 2, 2010 by Angela*

**Financ**

What are your client’s investment proportions in your three stocks and the T-bill fund? c. What is the standard deviation of the rate of return on your client’s portfolio?
*August 11, 2010 by sam*

**MATH**

Find the z-score related to the raw score, mean, and standard deviation as follows. Assume a normal probability distribution.
*August 19, 2010 by Anonymous*

**math**

Find the standard deviation for the given data. Round your answer to one more decimal place than original data. 2,5,47,11,13,48,39,36
*September 3, 2010 by Ella*

**statistics**

The heights of a large population of students have a mean of 60" with a standard deviation of 3". What is the mean of the resulting distribution of sample means for n =16?
*October 17, 2010 by Audrey*

**Statistics**

In a sample of 171, the mean is 58 with a population standard deviation of 4.8. Can someone help me figure out what is the 90% confidence interval of the true mean? Thank you.
*October 26, 2010 by Diandra*

**statistics**

SAT scores are normally distributed with a mean of 1518 and a standard deviation of 325. What scores correspond to P20 and P65?
*November 27, 2010 by Jacob*

**Math**

Find the standard deviation for the given data. Round your answer to one more decimal place than the original data. 2, 5, 47, 11, 13, 48, 39, 36
*December 9, 2010 by Rena *

**statistics**

Suppose that a coin is tossed 100 times. Let X be the number of times that it shows heads. Find the mean and standard deviation of X.
*December 13, 2010 by Mschribe*

**Statistics**

Given that the mean is 40 and the standard deviation is 1.5: A) what is the probability of selecting a value between 39 and 46 B)what value will allow only 15% of the data to be greater than it
*March 30, 2011 by Glenn*

**statistics**

which has a larger standard deviation: the distribution of weekly allowances to 12-year olds or the distribution of monthly household mortgage payments?
*April 6, 2011 by Jerome*

**statistics**

Scores on a recent national statistics exam were normally distributed with a mean of 80 and a standard deviation of 6. What is the percentile rank of a score of 89?
*July 7, 2011 by Anonymous*

**Stats**

Start with x=75 and add four x values to make a smaple of five data such that the standard deviation of these data equals 0.
*October 15, 2011 by Jennifer*

**statistics**

Assume that IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. Assume 1000 freshmen took the test.
*February 22, 2012 by Anonymous*

**statistics **

A test has a mean of 104 and a standard deviation of 16. We want to be 98% certain that we are within 4 points of the true mean. Determine the sample size.
*April 23, 2012 by Sabrina*

**Math**

The mean of a set of normally distributed data is 550 and the standard deviation is 35. What percent of the data is between 515 and 585?
*May 8, 2012 by nichole*

**Statistics**

start with X=100 and add four x values to make a samle of 5 data such that the standard deviation of these data equals 0
*November 16, 2012 by Jerry*

**statistics**

The mean of a normally distributed data set is 226.2. The data item, 230, has a z-score of 0.2. Find the standard deviation.
*January 16, 2013 by Anonymous*

**math**

the mean life of a tire is 30,000 km. the standard deviation is 2000 km. 68% of all tires will have a life between _km and _ km
*January 17, 2013 by Antonee*

**Excel help**

How would I write a formula to multiply the number in cell k4 times the standard deviation of the numbers in cell z2 through z10
*January 27, 2013 by Kimberly*

**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*

**Stats**

In the library on a university campus, there is a sign in the elevator that indicates a limit of 16 persons. Further more, there is a weight limit of 2500 pounds. Assume the average weight of students, faculty and staff on campus is 150 pounds, the standard devaiton is 27 ...
*March 26, 2012 by Jane*

**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*

**statistic**

A random sample of size n = 72 is taken from a finite population of size N = 644 with mean μ = 239 and variance σ2 = 325. Use Table 1. a-1. Is it necessary to apply the finite population correction factor? Yes No a-2. Calculate the expected value and the standard ...
*February 5, 2015 by echo*

**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**

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**

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*