# Standard Deviation-What?

10,264 results, page 20

### statistics

A film alliance used a random sample of 50 U.S. citizens to estimate that the typical American spent 78 hours watching videos and DVDs last year. The standard deviation of this sample was 9 hours.

### statistics

The data below are the ages of a random sample of 8 men in a bar. It is known that the population of ages are normally distributed with a standard deviation of 11. Determine the 93% confidence interval estimate of the population mean. 50 70 22 36 59 39 27 47

### college statistics

assume the population of heights of female college students mean of 64.37 inches standard deviation of 6,26 in and random sample of 74 find p(x>65.25)B. find p(x>65.25)c. why is formulas required to solve a different than c.

### Statistics

A normally distributed population has a mean of 40 and a standard deviation of 12. What does the central limit theorem say about the sampling distribution of the mean if samples of size 100 are drawn from this population.

### math

The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with a standard deviation of 0.3 minute. The percentage of a runners that will run the mile in less than 4 minutes is %.

### Statistics

On the daily run of an express bus, the average number of passengers is 48. The standard deviation is 3. Assume the variable is normally distributed. Find the probability that the bus will have Between 36 and 40 passengers

### statistics

It is claimed the average age of employee in a large company is 50. A sample of 36 employees is taken and the average age was 49. The standard deviation of the population was 5. Use a level of significance of .05. What do you think of this claim?

### statistics

Typing speeds among college students are normally distributed with a mean of 60 words, and a standard deviation of 10 words. determine the typing speed that separates the top 6% typists from the rest.

### Math

The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. How do I find the 80th percentile for these weights?

### UNION UNIVERSITY

Find the Z score for the weights of Middle school boys which are approximately Normal, mean = 130 lbs, Standard Deviation = 7, if Johnny weighs 148 lbs, What's his Z score?

### math

The amount of Jen’s monthly phone bill is normally distributed with a mean of \$50 and a standard deviation of \$10. Find the 25th percentile. A. About \$46.30 B. About \$43.30 C. About \$43.40 D. about \$43.20 I came up with \$43.26 which its not a choice. Please help!!

### math

The amount of Jen’s monthly phone bill is normally distributed with a mean of \$50 and a standard deviation of \$10. Find the 25th percentile. A. About \$46.30 B. About \$43.30 C. About \$43.40 D. about \$43.20 I came up with \$43.26 which its not a choice. Please help!!

### statistics definition

i have to find definitions and describe 208 words in my statistics class and for one of them it says: describe the deviation from a pattern of a graph. i don't actually get what it's asking me. i don't think it's pattern becuase i already have the definition for that. when it ...

Compute the standard deviation for stress. Determine where participants fall in relation to the mean. (Create a diagram that depicts where students fall in relation to standard deviations around the mean. Participant Group Fights Stress 1 PSY 7 86 2 PSY 3 84 3 PSY 5 92 4 PSY 4...

### Math

At the end of the first quarter of 2006, all the major stock market indexes had posted strong gains in the past 12 months. Mass Mutual Financial Group credited the increases to solid growth in corporate profits. The mean one-year return for stocks in the S&P 500, a group of ...

### statistics

confidence intervals: A researcher is interested in estimating the average salary of teachers in a large school district. She wants to be 95% confident that her estimate is correct. If the standard deviation is \$1050, how large a sample is needed to be accurate within \$200.

### statstics

construct a 90 confidence interval for the population mean ÃŽ¼. assume the population has a normal distribution. A sample if 15 randomly selected math majors has a grade point average of 2.86 with a standard deviation od 0.78. Round to the nearest hundredth

### statistics

Solve the problem. Round to the nearest tenth unless indicated otherwise. The amount of rainfall in January in a certain city is normally distributed with a mean of 4.3 inches and a standard deviation of 0.3 inches. Find the value of the quartile .

### math

A researcher is interested in estimating the average salary of Police officers in a large city. she want to be 95% confident that her estimate is correct. If the standard deviation is \$1050, how large a sample is needed to get the desired information and to be accurate within...

### Math

The following set of numbers respresents the average weekly scores of 9 preschoolers on a verbal aggression scale. 19.1, 18.9, 33.5, 18.7, 28.1, 31.5, 20.3, 30.1, 17.9 Consider this to be the entire population of scores. What is the standard deviation? I already have the mean ...

### stat

Construct a 90% confidence interval for the population mean. Assume the population has a normal distribution. A same of 15 randomly selected math majors has a grade point average of 2.86 with a standard deviation of 0.78. Round to the nearest hundredth. Answers: a) (2.41,3.42...

### science

the mean weight of 500 males students at a certain college is 151 lb and standard deviation is 15lb .assuming the weights are normally distributed, find how many students weigh between 120 and 155 lb ..ii) more than 185 lb

### Stats 123

A scratch-card costs 5¤ and has two possible prizes. There is a 10% chance you get 5¤ back and a 1% chance you get 100¤. In all other cases, you get nothing. Let X denote your net winnings, i.e, (X = prize - cost). What are the expectation and standard deviation of X?

### Can comeone check my answer for me. Many Thanks!

A set of data is normally distributed with a mean of 1000 and standard deviation of 100. · What would be the standard score for a score of 1100? · What percentage of scores is between 1000 and 1100? · What would be the percentile rank for a score of 1100? A. z(1100)= (1100-...

### Statistics

Foofy says a deviation of +5 is always better than a deviation of -5. Why is she correct or incorrect?

### statistics

A laptop computer manufacturer found that by improving their battery design, they could increase the time that the laptop computer could be used on a single charge. To verify this improvement, they compared a sample of 10 laptops installed with the improved batteries to a ...

### statistics

A continuously running washing machine receives jolts in a Poisson process at an average rate of 10 jolts per hour. The standard deviation of the number of jolts received in given 20 minute run is equal to

### math

The population mean length of a hospital stay for surgery is 5.5 days and the standard deviation is 1.9 days. What percentage of patients are hospitalized for 3.9 days or less? I've read the book and looked at the explanation that it gives and it's not making any sense.

### math

the courier service company has found that their time of parcels to client is normally distributed with a mean of 45 minutes and a standard deviation of 8 minutes. the probability that a randomly selected parcel will take less than 48 minutes to deliver is

### STATS

. The time to fly between New York City and Chicago is normally distributed with a mean of 180 minutes and a standard deviation of 17 minutes. What is the z-score that corresponds to a random variable X outcome of 190 minutes?

### math

In a large population of adults, the mean IQ is 112 with a standard deviation of 20. Suppose 200 adults are randomly selected for a market research campaign. The probability that the sample mean IQ is greater than 110 is...?

### math

The weights of extra large eggs have a normal distribution with a mean of one ounce and a standard deviation of 0.1 ounces. The probability that a dozen eggs weighs more than 13 ounces is closest to...?

### Pre-cal

A set of data is normally distributed with a mean of 16 and a standard deviation of 0.3. What percent of the data is between 15.2 and 16? I had: 16-t(0.3)=15.2 and 16-t(0.3)=15.7 which came to 0.497-.341=0.156. rounded off I came up with 16%. What did I do wrong?? Thanks

### Data Management

How many of the 250 perch netted by a fisherman would you expect to have a mass more than 400g if the mass of the perch are normally distributed with a mean of 300g and a standard deviation of 80g.

### Data Management

How many of the 250 perch netted by a fisherman would you expect to have a mass more than 400g if the mass of the perch are normally distributed with a mean of 300g and a standard deviation of 80g.

### Statistics

The weights of the fish in a certain lake are normally distributed with a mean of 11 lb and a standard deviation of 6. If 4 fish are randomly selected, what is the probability that the mean weight will be between 8.6 and 14.6 lb? A) 0.0968 B) 0.4032 C) 0.3270 D) 0.6730

### statistics

Approximately 16% of undergraduates at the University have a writing score above 68 (on a 100 point scale). Note: writing scores are normally distributed. if a standard deviation is 8 what is the mean writting score

### statistics

The IQ of 100 college students in XYZ univ are found to be normally distributed where mean is 105 and standard deviation is 8. If the student IQ score is 90, what is the probability that another student randomly slected has an IQ score of below 90.

### statistics

A researcher randomly selects 37 subjects and administers an attitude test regarding a product. Their mean is 22 and their standard deviation is 2.4. Construct the 90% confidence interval for the mean score of all such subjects

### Math

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?

### educational statics

how often does the university admit an exception student with a SAT score of x =700 or above Asample of 36 students (N)- 36 were randomly selected with mean (=11,and standard deviation (x=12. the sample mean score X=9.

### algebra/math

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 40 people. (a) How many would you expect to be between 158 and 172 cm tall?

### statistics

1) A scale measuring prejudice has been administered to a large sample of respondents. The distribution of scores is approximately normal with a mean of 31 and a standard deviation of 5. What percentage of sample had scores below 20?

### Statistics

Scores on the Stanford-Binet Intelligence scale have a mean of 100 and a standard deviation of 16, and are presumed to be normally distributed. A person who scores 68 on this scale has what percentile rank within the population?

### statistics

The average middle-distance runner at a local high school runs the mile in 4.5 minutes, with a standard deviation of 0.3 minute. Find the percentage of a runners that will run the mile in less than 4 minutes?

### statistics

The mean life of a set of batteries in a T83 calculator is 525 with a standard deviation of 35 hours assume normal distribution is normal whats is the probability that set will last for more the 540 hrs

### statistics

The average electric bill in a residential area is \$72 for the month of May. The standard deviation is \$6. If the amounts of electric bills are normally distributed, find the probability that the mean of the bill for 15 residents will be less thatn \$75

### Statics

An automotive engineer wants to use 64 test runs to estimate the true mean tire stopping distance. The standard deviation is assumed to be 32 feet. What is the probability that the error of the estimate will be more than 4 feet?

### Statistics

Consider a basketball game where a player throws from the free throw line. Her success rate is 65%. If she throws 10 times in a game determine the following:The mean and standard deviation of this binomial distribution.

### math check

Consider the following set of data. Pairs 1 2 3 4 5 Sample A 2 8 7 9 2 Sample B 7 8 1 1 8 Find the standard deviation sd of the paired differences. (Give your answer correct to two decimal places.) My answer was 5.00.

### mah statistics

the following table gives the number of camcorders sold on a given day in an electronics store X: 0, 1, 2, 3, 4, 5, 5, P(x) 0.5, .12, .23, .3, .16, .1, .04 find the mean, variance, and standard deviation of the daily sales of camcorders in the store.

### Statistics

The weights of male babies less than 2 months old in the United States is normally distributed with a mean of 11.5 pounds and a standard deviation of 2.7 pounds. Find the 80th percentile score for these weights.

### math probability

Daytime high temperatures in New York in February are normally distributed with an average of 30.2º and a standard deviation of 8.5º. Estimate the probability that the temperature on a given day in February is 39º or higher.

### statistics

A food manufacturer samples 7 bags of pretzels off the assembly line and weighs their contents. If the sample mean is 14.2 oz and the sample standard deviation is 0.60 oz., find the 95% confidence interval of the true mean.

Find warranty period (in days) for a washing machine whos average (mean) life is 6 years and standard deviation of 2.5 years. Assume 365 days in a year.

Find warranty period (in days) for a washing machine whos average (mean) life is 6 years and standard deviation of 2.5 years. Assume 365 days in a year.

### stats

glucose level in patients free of diabetes are assumed to follow a normal distribution with a mean of 120 and a standard deviation of 16. (20 pts) What proportion of patients has glucose levels exceeding 115?

### math

Suppose the scores of students on an exam are normally distributed with a mean of 393 and a standard deviation of 57. According to the empirical rule, what percentage of students scored between 279 and 507 on the exam

### Statistics

Scores on an SAT test have a mean of μ = 1026 and a standard deviation of σ = 209. Compute the margin of error of the sample mean for a random sample of 100 students.

### math

Find the z-score for the given raw score, mean, and standard deviation. Assume a normal probability distribution. Raw score = 15, ì = 16 , and ó = 2

### statistics

a math test has a mean of 43 and a standard deviation of 17.0. find the corrresponding z scores for a test score of 13 and a test score of 59. show work

### statistics

A normal population has a mean of 21 and a standard deviation of 5. Compute the z value associated with 24 What proportion of the population is between 21 and 24? What proportion of the population is less than 18?

### 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

### Statistics

The diameter of an electric cable is normally distributed, with a mean of 0.7 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.71 inch?

### statistics

The diameter of an electric cable is normally distributed, with a mean of 0.7 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.71 inch?

### UNM

Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms. 42% of the students weights are above what kilograms?

### UNM

Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms. 45% of the students weights are above what kilograms?

### math

The diameter of an electric cable is normally distributed, with a mean of 0.6 inch and a standard deviation of 0.01 inch. What is the probability that the diameter will exceed 0.61 inch?

### math

A class of 43 students took an exam. They had a mean average of 67 and a standard deviation of 7. a) how many students got a c b) how many students got a b c) what is a scoree needed to get an a is a) 4 b) 1 c) 90

### Statistics

If a completion time for a task is normally distributed with a mean of 15 seconds and a standard deviation of 2.5 seconds, what is the probability of getting a time less than 9.7 seconds?

### statistics

a math test has a mean of 43 and a standard deviation of 17.0. find the corresponding z scores for a test score of 13 and a test score of 59. show all work.

### Math

The volumes of soda in quart soda bottles are normally distributed with a mean of 32.3 oz and a standard deviation of 1.2 oz. What percentage of bottles contain less than 32 oz of soda?

### Statistics

Assuming that the heights of college women are normally distributed with mean 66 inches and standard deviation 2 inches, what percentage of women are shorter than 72 inches?

### Math

The mean time to complete a certain stat quiz is 25 minutes, with a standard deviation of 5 minutes. Find the probability of a student taking. 1.) less than 15 minutes. 2.) Between 15 and 25 minutes. 3.)more than 25 minutes.

### math

Find the z-score for the given raw score, mean, and standard deviation. Assume a normal probability distribution. Raw score = 124, μ = 98, and o = 17 A) 0.65 B) -1.53 C) -0.65 D) 1.53

### college, statistics

a math test has a mean of 43 and a standard deviation 0f 17.0. find the corresponding z scores for. show all work. I. a test score of 13 II. a test score of 59

### Statistics

Suppose that weights are bell shaped with a mean of 120 pounds and a standard deviation of 10 pounds. What percentage of weights is between 110 and 130 pounds

### statistics

The heights of 500 boys are measured and found to be normally distrubuted with a mean of 66 inches and a standard deviation of 2 inches.About how many boys are taller than 68 inches?

### statistics

ER promises you will be seen in 10 minutes. the standard deviation is 2 minutes. chance someone will wait more than 13 minutes. i don't know what to do without a population size or sample size

### UNM

Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms. What percent of students have weights greater than 80.1 kilograms?

### STATS

Suppose that the average weight of students in a statistics class is 75.5 kilograms with a standard deviation of 10.3 kilograms. B. What percent of students have weights greater than 80.1 kilograms?

### statistics

1)Let X have a normal distribution with mean 6 and standard deviation 3. a) What is the probability that X > 8.7 2)What is the probability that X<0? 3)What is the probability that |X-6| > 1.9 ? I have got so far: P(Z > 0.9) but I do not know where to go from here! ...

### Statistic 103

The average teachers salary in Connecticut( ranked first among states) is \$57,337. suppose that the distribution of salaries is normal with a standard deviation of \$7500. What is the probability that a randomaly selected teacher makes less than \$52,000 per year?

A random sample of six CEOs reported how many times per year they play tennis. The data follows. 3 41 96 32 52 19 Assuming the number of games played is normally distributed and the population standard deviation σ = 10, a 95% confidence interval for μ is:

### statistics check my work thank you

what is the sample size, mean, and standard deviation for patients who were given and NOT given antiobiotics (key 1= yes 2=no) Received Antibio Duration of stay in hosp 2 5 2 10 2 6 2 11 2 5 1 14 1 30 2 11 2 17 2 3 2 9 2 3 1 8 1 8 2 5 2 5 1 7 2 4 1 3 2 7 2 9 1 11 2 11 2 9 2 4...

### math

what is the z-score for the given raw score, mean and standard deviation, assume a normal probability dist. raw score=66,u=60, and 0=6 u and o are those wierd symbols is the answer 1, 10, 6, or 66

### Algebra 2: Prob and Stats

The numbers of cookies in a shipment of bags are normally distributed, with a mean of 64 and a standard deviation of 4. What percent of bags of cookies will contain between 60 and 68 cookies? * 50% * 13.5% * 68% * 34%

### statistics

The lengths of pregnancies are normally distributed with a mean of 268 days and a standard deviation of 15 days. Out of 50 pregnancies, how many would you expect to last less than 250 days?

### statistics

Percentage grades in a large physics class follow a normal distribution with mean 58. It is known that 3% of students receive grades less than 39.2. What is the standard deviation of grades in the class?

### Statistics

The distribution of heights of adult American men is approximately normal with a mean of 68 inches and a standard deviation of 2 inches. What percent of mean are at least 72 inches tall?

### math

The distribution of heights of adult American men is approximately normal with a mean of 68 inches and a standard deviation of 2 inches. What percent of mean are at least 72 inches tall? Thanks!!

### statistics

Height of children in kindergarten described by normal mode with mean 39.2 inches and standard deviation of 1.9 inches. What percent of children can expect to be less than 38 inches tall?

### quanitative methods

The time required to complete a project is known to be normally distributed with a mean of 44 weeks and a standard deviation of 8 weeks. (a) What is the probability that the project is finished in 40 weeks or fewer?

### statistics

If 1,000 students take a test that has a mean of 40 minutes, a standard deviation of 8 minutes, and is normally distributed, how many would you expect would finish in between 24 and 48 minutes?

### Math

Suppose you have a mean standardized score of 1500 points with a standard deviation of 150 points. This data is normally distributed. What is the z-score of 1600 points? 0.75 0.5 0.67 0.32

### Algebra 2

The heights of 200 kindergarten students are normally distributed with a mean of 40 and a standard deviation of 1.8 inches. Approximately how many students have a height between 37.3 inches and 44.5 inches?

### statistics

at a bank, account balances are nomrally distribued with a mean of \$637.52 and standard deviation of \$623.16. What is the probability that a simple randon same of 400 accounts has mean that exceeds \$1650.00? show me steps and calculations i urgently need help

### statistics

Please let me know if I solved this right The lifetime of television produced by the Hishobi Company are normally distributed with a mean of 75 months and a standard deviation of 8 months. If the manufacturer wants to have to replace only 1% of its televisions, what should its...

### statistics

1. The average number of articles produced by two machines per day is 200 and 250 with standard deviation 20 and 25 respectively on the basis of records of 25 days production. Can you regard both the machines equally efficient at 1% level of significance?

### statistics

A balloon mannufacturer kows that historically her company has produced 614 balloons per day (standard deviation =36) she has changed the process and wants to know wheathert he new process is increased the number of ballons made. the sample mean is 620. 0.5, n=16