Friday

February 24, 2017
Number of results: 10,024

**Math**

A district mathematics test for third-graders had a normal distribution with a mean of 74 and a standard deviation of 11. What percentage of students scored between 63 and 85?

*February 15, 2016 by Clement*

**Statistics**

If a normally distributed group of test scores have a mean of 76 and a standard deviation of 10. Find the probability that student will earn a grade between 65 and 85

*April 9, 2016 by Joe*

**Statistics**

Find the number x such that the proportion of observations that are less than x in a Normal distribution with mean 100 and standard deviation 25 is 0.3. (Use 2 decimal places.)

*May 31, 2016 by Sarah Lacks*

**Statistics**

An observation was drawn from a normally distributed population with mean 2.397 and standard deviation 0.612. If the observed value is 3.144, find the z-score.

*January 22, 2017 by Karyn*

**math**

weekly take home pay for those 20 graduate teaching assistants from university z: 500.75, 217.43, 488.25, 405.78 485.46, 495.48, 370.75, 435.40 479.65, 482.56, 470.28, 489.90 382.50, 500.75, 465.32, 481.25 506.43, 225.50, 504.38, 179.25 1. what are the mean and standard ...

*April 13, 2011 by mary*

**statistics**

Over the past several months, an adult patient has been treated for tetany (severe muscle spasms). This condition is associated with an average total calcium level below 6 mg/dl. Recently, the patient's total calcium tests gave the following readings (in mg/dl). Assume that ...

*April 11, 2015 by Interval Estimate*

**ALGBRA**

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). -------------------------------- I've posted this question earlier and I'm still getting the wrong answer. I ...

*December 4, 2012 by Debin*

**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). -------------------------------- I've posted this question earlier and I'm still getting the wrong answer. I ...

*December 4, 2012 by Debin*

**Statistics**

A statistics professor gives a test and finds that the scores are normally distributed with a mean of 25 (out of 100) and a standard deviation of 5. She plans to curve the scores in one of two ways. 1) She could add 50 points to each grade. 2) She could use the following ...

*July 5, 2011 by Nikki*

**Math**

For a specific type of machine part being produced, the diameter is normally distributed, with a mean of 15.000 cm and a standard deviation of 0.030 cm. Machine parts with a diameter more than 2 standard deviations away from the mean are rejected. If 15,000 machine parts are ...

*February 9, 2016 by Ashley Colley*

**statistics**

The Acme Company has developed a new battery. The engineer in charge claims that the new battery will operate continuously for at leas 7 minutes longer than the old battery. To test the claim, the company selects a simple random sample of 100 new batteries and 100 old ...

*February 16, 2012 by Maria E. S.*

**math**

Calculate the range, standard deviation, and interquartile range for the data set: {-1, 0, 1, 2, -1, 0, 1, 2, -1, 0, 1, 2, 1, 1, -2}

*February 27, 2010 by Jillian*

**Data and Statistics**

Calculate the z score for an ACT score of 12, a mean of 20, and the standard deviation is 5.

*July 22, 2010 by Beverly*

**statistics**

if the mean is 20 and the standard deviation is 4, at least what percentage will have a mean between 15 and 25?

*June 20, 2011 by danette*

**statistics**

Mean class scored 74 w/ standard deviation of 4.3. What is range of scores for 68% of class?

*January 10, 2012 by Joe*

**Statisticis**

16. Describe what is measured by the mean and what is measured by the standard deviation for a set of scores.

*September 17, 2012 by Mary beth*

**statistics**

true or false The value for the standard deviation cannot be larger than the value for the range.

*January 3, 2014 by Lyndyc*

**statistics**

For a population with a mean of 80 and a standard deviation of 10, what is the Z score corresponding to an individual score of 95?

*June 8, 2016 by tonya*

**math**

weekly take home pay for those 20 graduate teaching assistants from university z: 500.75, 217.43, 488.25, 405.78 485.46, 495.48, 370.75, 435.40 479.65, 482.56, 470.28, 489.90 382.50, 500.75, 465.32, 481.25 506.43, 225.50, 504.38, 179.25 1. what are the mean and standard ...

*April 12, 2011 by Mary*

**chemistry**

Just..... don't get it A column packing for chromatography consists of a mixture of two types of particles. Assume that the particles in the batch being sampled are spherical with a radius of 0.5 mm. 36% of the particles appeared to be pink and are known to have a polymeric ...

*March 29, 2010 by Sai*

**statistics**

For a sample with a mean of M=45, a score of x=59 corresponds to z=2.00.What is the sample standard deviation?

*January 31, 2011 by Dana*

**statistics**

For a sample with a mean of M 45, a score of 59 corresponds to z 2.00. What is the sample standard deviation?

*March 7, 2011 by olga*

**statistics**

There are 20 numbers, the highest is 91, the lowest is 34. The mean is 60 and the standard deviation is 5. What are the 20 numbers?

*June 27, 2011 by Annie*

**statistics**

There are 20 numbers, the highest is 91, the lowest is 34. The mean is 60 and the standard deviation is 5. What are the 20 numbers?

*June 27, 2011 by Annie*

**statistic**

a population of n = 100 score has u = 30 and standard deviation =4 what is the population variance

*September 26, 2011 by mary*

**Statistics**

Find the Standard Deviation for this distribution of scores. Then find the z score for X=86. N=17 98, 92, 86, 84 , 76, 74 , 72 , 72, 72 , 70, 70, 66, 60 ,54, 32,30

*December 7, 2013 by Lyndyc*

**statistics**

what is the weight between 5.5 to 6 ounce when mean is 5,75 ounce and standard deviation is 0.11

*November 7, 2014 by Anonymous*

**statistics**

Consider the following. (a) What percentage of a normal distribution is greater than the mean? (Give your answer correct to the nearest percent.) Incorrect: Your answer is incorrect. . % (b) What percentage is within 1 standard deviation of the mean? (Give your answer correct ...

*May 26, 2013 by Gayle*

**Statistics**

Consider the following. (a) What percentage of a normal distribution is greater than the mean? (Give your answer correct to the nearest percent.) Incorrect: Your answer is incorrect. . % (b) What percentage is within 1 standard deviation of the mean? (Give your answer correct ...

*May 27, 2013 by Gayle*

**math**

Consider the following. (a) What percentage of a normal distribution is greater than the mean? (Give your answer correct to the nearest percent.) Incorrect: Your answer is incorrect. . % (b) What percentage is within 1 standard deviation of the mean? (Give your answer correct ...

*May 30, 2013 by Nora 2*

**math**

Suppose that people's heights (in centimeters) are normally distributed, with a mean of 170 and a standard deviation of 5. We find the heights of 60 people. (You may need to use the standard normal distribution table. Round your answers to the nearest whole number.) (a) How ...

*December 3, 2013 by Anonymous*

**math**

A standard deck of cards is made up of four suits with 13 cards in each suits (total of 52 cards). If we randomly sample five cards from a standard deviation of $6000. What is the cutoff salary for teachers in the bottom 10%? Answer choice: a) 5/2,598,960 b) 1287/2,598,960 c)...

*April 16, 2010 by nicole*

**statistics**

A score that is 10 points below the mean corresponds to a z-score of z=-2.00. What is the population standard deviation?

*February 5, 2008 by Joan*

**Stats**

True or false: The distribution with the largest range necessarily has the largest standard deviation.

*January 22, 2010 by KLM*

**statistics**

In a distribution of scores, X=62 corresponds to z=+0.50, and X=52 corrsponds to z=-2.00. Find the mean and standard deviation for the distribution.

*June 20, 2010 by dray*

**Statistics**

In a given normal distribution, the standard deviation is 14.4 and 8.27% of the distribution lies to the left of 60. What is the mean?

*October 3, 2010 by Lori*

**statistics**

A score that is 6 points below the mean corresponds to a z-score of z= - .50, what is the population standard deviation?

*March 9, 2012 by Amy*

**statistics**

1. On a measure of anxiety, the mean is 79 and the standard deviation is 12. What are the z-scores for each of the following raw scores?

*March 10, 2012 by bertha*

**maths a**

us e the formula z=x-u/SD to determine the z score for a score of 34.5 a normal distribution if the mean is 46.5 and the standard deviation is 8.7

*September 11, 2014 by jay*

**Psychological Statistics**

For a population with a mean of 80 and a standard deviation of 12, what is the Z score corresponding to an individual score of 92

*January 7, 2015 by Anonymous*

**math**

a sample consists of the following n =6 scores: 2, 7, 4, 6, 4, and 7 compute the mean and standard deviation for the sample

*February 16, 2015 by Bridget*

**statistics**

Average is 8500 with a standard deviation. Of 1500 with a z score of -2.98 a z score of +1.00 what are the actual bonuses

*July 7, 2015 by Anonymous*

**Psychological Stats**

For a population with a mean of 80 and the standard deviation of 12, what is the Z score corresponding to an individual score of 71?

*June 23, 2016 by Tara*

**Statistics**

If the standard deviation of a sample is 12 inches, then the variance is 144 sq. inches. Do you agree? Can you try?

*January 22, 2017 by Elegantina*

**statistics**

the correlation between two tests given to 100 students in the junior clas is .70 the mean for the first test was 125 with standard deviation 20 the mean of the second test is 80 with standard devation 10 a student took the first test and scored 100. what is your best estimate...

*March 4, 2012 by Anonymous*

**Math**

The systolic blood pressure of 18-year-old women is normally distributed with a mean of 120 mm Hg and a standard deviation of 12 mm Hg. What percentage of 18-year-old women have a systolic blood pressure that is within 3 standard deviations of the mean on either side? Apply ...

*May 4, 2016 by angela*

**finite math**

1. what are the mean and standard deviation for this distribution of weekly take-home pay amounts? 2. what percentage of the pay amounts lie within 1 standard deviations of the mean? 3. what percentage of the pay amounts lie within 2 standard deviations of the mean? 4. what ...

*April 14, 2011 by margie*

**Algebra**

1)A bookshelf holds 4 mysteries, 3 biograpghies, 1 book of poetry, and 2 reference books. If a book is selected at random from the shelf, find the probability that the book selected is a biography or reference book. A)1/2 B)1/6 C)5/6 D)3/50 I chose A 5 bio/reference/10 total ...

*February 22, 2008 by Jon*

**math**

If a group of data has a mean of 19 and a standard deviation of 77.8, what is the interval that should contain at least 88.9% of the data?

*June 8, 2009 by Rachel*

**Statistics**

How is finding the standard deviation a measurement of a data\'s center? my teacher said it measured the center...

*August 28, 2009 by Statistics*

**math**

calculate the range, variance, standard deviation, and interquartile range for the data set given {72, 80, 80, 82, 88, 90, 96}

*October 11, 2009 by please help*

**Math**

calculate the range, variance, standard deviation, and interquartile range for the data set given {72, 80, 80, 82, 88, 90, 96}

*November 1, 2009 by Anonymous*

**math**

A set of data is normally distributed with a mean of 16 and a standard deviation of 0.03. What percent of the data is between 15.2 and 16?

*March 10, 2010 by Sally*

**Math**

calculate the range, variance, standard deviation, and interquartile range for the data set given {72, 80, 80, 82, 88, 90, 96}

*December 12, 2010 by Dominick*

**Statistics**

A random sample is obtained from a normal population with a mean that equals 80 and a standard deviation that equals 8

*March 12, 2011 by Jim*

**statistics**

If there are 200 students in a sample, and the mean = 45 and the standard deviation = 4. How many of these students will have a score under 41?

*November 14, 2011 by Julie*

**maths**

A loaf of bread is normally distributed with a mean of 22 oz and a standard deviation of 0.5 oz. What is the probability that a loaf is larger than 21 oz?

*January 31, 2012 by atul*

**statistics**

if the mean of a test score is 30 and the standard deviation is 3.7. which score could be expected to occur the least often?

*March 12, 2012 by Anonymous*

**stastics**

A population has mean 53 and standard deviation 12. Calculate the mean of x bar for a random sample of size 10.

*November 11, 2012 by Anonymous*

**psyc**

A normal distribution has µ = 80 and standard deviation = 10. What is the probability of randomly selecting a score greater than 75 from this distribution?

*March 3, 2013 by shauna*

**statistics**

the average score on the statistics quiz was a 70, and there was a standard deviation of 10 points. If the z-socre was -1.0 what is the percentile rank?

*March 2, 2014 by kim*

**math**

The test scores for a math class are shown below 83,85,82,93,83,84,95,87,86,94 what is the standard deviation of the data set?

*May 19, 2014 by heather*

**statistics**

there are 500 passenger with a mean age of 60 years and a standard deviation of 12. what is the minimum age of the oldest 20%?

*April 19, 2015 by Busisiwe*

**TP**

What is Standard Deviation? As in what does it measure, is it a measure of spread of a graph of results?

*May 29, 2008 by Maths*

**algebra 2**

how do i set up data to find the standard deviation of the data?

*May 6, 2010 by chicken littell*

**algebra 2**

how do i set up data to find the standard deviation of the data?

*May 6, 2010 by chicken littell*

**Math**

what is a range, variance, standard deviation, and interquartile range

*December 12, 2010 by Dominick*

**Statistics**

What will adding 50 to each score in a distribution do to the standard deviation of that distribution?

*November 24, 2011 by Brea*

**variation**

IF arithmetic mean is 10 and V(X)=4 find mean and standard deviation of z where Z=5x+4

*December 1, 2011 by Anonymous*

**statistics**

An experiment was conducted to determine the abrasion resistance of a new type of automobile paint. Twelve different strips of metal were painted with the new paint. The abrasion resistance of each piece was then tested on a machine. In the sample, the abrasion resistance ...

*April 2, 2014 by Nicky*

**statistics**

A normal distribution has a mean = 100. Find its standard deviation if 17% of the values exceed 144. All I can say is wow. Book is of no help. Neither is teacher. Can anyone help?

*March 11, 2008 by Mete*

**Statistical Methods**

The mean price of purchases is $110 and the standard deviation = $12. What is the probability of a purchase exceeding $90? I need help reviewing. Please give some input.

*March 11, 2008 by Mete*

**statistics**

Scores on a test are normally distributed with a mean of 68.2 and a standard deviation of 10.4. Estimate the probability that among 75 randomly selscted students, at least 20 of them score greater that 78.

*April 13, 2008 by Jean*

**Statistics**

The high temperature X (in degrees Fahrenheit) on January days in Columbus, Ohio varies according to the Normal distribution with mean 21 and standard deviation 10. the value of P(X<10)is?

*March 13, 2010 by Anonymous*

**Statistics**

The high temperature X (in degrees Fahrenheit) on January days in Columbus, Ohio varies according to the Normal distribution with mean 21 and standard deviation 10. the value of P(X<10)is?

*March 13, 2010 by Anonymous*

**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 don't know why .. PLEASE help!

*January 20, 2011 by Tami*

**math**

identify what is the 90 percent confidence interval for occupational prestige for respondents with only a bachelor's degree (N=750), given you have known their mean=52.74, standard deviation=12.67.

*April 4, 2011 by Nancy*

**math**

Use Chebyshev’s theorem to find what percent of the values will fall between 162 and 292 for a data set with a mean of 227 and standard deviation of 13.

*June 23, 2011 by denise*

**statistics**

For the following scores, find the (a) mean, (b) median, (c) sum of squared deviations, (d) variance, and (e) standard deviation: 1,112; 1,245; 1,361; 1,372; 1,472

*August 14, 2011 by Donna*

**statistics**

cost of producing is 50 cents each and they sell for 1.25 each. demand for programs at each game is normally distributed with a mean of 2500 and standard deviation if 200. how many shouild be prodcued

*November 19, 2011 by Anonymous*

**statistics**

assume that adults have IQ scores that are normally distributed with a mean of 100 and a standard deviation of 20. find the probability that a randomly selected adult has an IQ less than 20.

*March 14, 2012 by samantha*

**statistics**

psychologist wants to interview subjects with IQ scores are normally distributed with mean of 100 and standard deviation of 15. find the score that separating the top of IQ frin the bottom 90%

*May 9, 2012 by joe*

**Statistics for Social Science**

A random sample of 80 students at a largae school shows an average grade of 72 in Algebra with a standard deviation of 4. Find the standar error.

*November 24, 2012 by Pearl*

**statistics**

sample size needed with a mean of 100,standard deviation of 20 for the the population of normal adults an iq range to fall between 2 iq points with 95% confidence interval

*December 1, 2012 by krissy*

**Statics**

A candy machine distributor collects the coins from 100 machines. The standard deviation is $3.25. With probability 98%, what is the maximum error about the true mean that will result?

*December 1, 2012 by Heather*

**Biostats**

If the average (xbar) on an assignment in a class was 82% with a standard deviation (s) of 4.8, what is the z-score for someone scoring 75% (round to the one hundredths place or two decimal places)?

*February 3, 2013 by brittany*

**statistics**

I need a estimate within $25, the true average of amount of postage a company spends each year. If I want to be 98% confident, how large a sample is necessary? The standard deviation is known to be $80

*March 29, 2013 by ann*

**Stats**

The high temperature X (in degrees Fahrenheit) on January days in Columbus, Ohio varies according to the Normal distribution with mean 21 and standard deviation 10. The value of P(X < 10) is

*March 29, 2014 by Tracy*

**statistics**

How large a sample should be selected to provide a 95% confidence interval with a margin of error of 10 (to the nearest whole number)? Assume that the population standard deviation is 40.

*April 21, 2014 by Vanessa*

**data analysis**

A survey of 1500 college students found that 675 stay on campus in a dorm. Find the mean and standard deviation of the proportion of the sample.

*May 20, 2014 by Anonymous*

**Math**

Scores on a marketing exam are known to be normally distribute with mean and standard deviation of 60 and 20, respectively. The syllabus suggests that the top 15% of the students will get an A in the course. What is the minimum score required to get an A?

*September 25, 2014 by Sam*

**statistics**

studies indicate that drinking water supplied by some old lead-lined city piping systems may contain harmful levels of lead. an important study of the Boston water supply system showed that the distribution of lead content readings for individual water specimens had a mean and...

*March 14, 2011 by dinhgde*

**chemistry**

This is super confusing complex brain killing A column packing for chromatography consists of a mixture of two types of particles. Assume that the particles in the batch being sampled are spherical with a radius of 0.5 mm. 36% of the particles appeared to be pink and are known...

*March 28, 2010 by Simon*

**physics**

If sigma(t)^2 denotes the standard deviation in the quantity t^2, show that sigma(t)^2=2tsigma(t) I don't even know where to begin... help plzz

*February 15, 2009 by Anna*

**Statitics**

25 periodicals have a mean of $180 and a standard deviation of $12. form a 95% confidence interval on the population mean.

*March 20, 2009 by Sally*

**STATISTICS**

Find the sample standard deviation s for the following sample data. Round your answer to the nearest hundredth. x: 23 20 11 33 27

*June 3, 2010 by Jake*

**Math**

Suppose the mean heights of a population are 72 inches with a standard deviation of 2 inches. What height (x) corresponds to the z value of 1

*May 14, 2011 by Phillip*

**math**

with a mean of 515 and a standard deviation of 135, what percentage score 110-515 using the 68-95-99.7 rule

*October 26, 2011 by Ron*

**Math**

Given the following frequency distribution, find the mean, variance, and standard deviation. Class Frequency 31-33 18 34-36 25

*November 10, 2011 by Jennifer*

**Math**

Given the following frequency distribution, find the mean, variance, and standard deviation. Class Frequency 31-33 18 34-36 25 37-39 22 40-42 9 43-45 20

*November 10, 2011 by Jennifer*