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Standard Deviation-What?

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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.

STATISTICS(PLEASE READ)
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.

please answer statistics
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?

Business Statistics
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:

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

statistics
The serum cholesterol levels for men in in one age group are normally distributed with mean of 178.1 and standard deviation of 40.8. All units are in mg/100ml. Find two levels that cut off the top 10% and the bottom 10 % from the distribution of x.

statistics
Assume that thermometer readings are normally distributed with a mean of 0.0 and a standard deviation of 1,00. the thermometer is randomly selected and tested. For the case below, draw a sketch , and find the probability of the reading The given values in Celsius degrees) ...

Basic Statistics
A researcher is interested in estimating the average salary of police officers in a large city. She wants 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...

state
A machine put the juice in the bottle with normal distribution with mean is equal to 50 cl, with the standard deviation 5 cl. Test was done to see if the claim is right. A sample of 100 bottles were tested. They got the average content of 48.9 cl. At ∝ =0.05, can the ...

Math
The results of a certain medical test are normally distributed with a mean of 130 and a standard deviation of 12. ​(A reading above 149 is considered​ unhealthy.) Use the given table to find the percentage of people with readings above 141.

Algebra
I do not understand this homework at all. Any help or elaboration would be greatly appreciated. Thanks. 100 juniors at Southwest High took the SAT test. The scores were distributed normally with a mean of 22 and a standard deviation of 3. Label the mean and three standard ...

maths
The data in table below gives marks for an exam of a particular tutors students in 2005 and 2006. Year students marks on the exam 2005 75 86 91 65 83 75 88 90 66 99 2006 60 78 75 98 79 90 80 88 81 90 from the following choose two options which are true about the table above. a...

Algebra 2
Suppose you did a survey of male shoes size and the mean of that survey was size 10 with a standard deviation of 1.5. What is the z-score of a size of 7.5?

Math
Suppose you did a survey of male shoes size and the mean of that survey was size 10 with a standard deviation of 1.5. What is the z-score of a size of 7.5?

Stats
A Math test has a mean of 51 and standard deviation of 5.0. Find the corresponding z scores for: I. a test score of 64 II. a test score of 47

probability
normally distributed with a mean of 40 minutes and a standard deviation of 5 minutes. What is the probability that it will take more than 40 minutes? Answer

Help please! Math
A car is designed to last an average of 12 years with a standard deviation of 0.8 years. What is the probability that a car will last less than 10 years?

Statistics
A criminologist is studying school violence, she selects a random sample of 25 adolescents aged 12 to 15 from a local middle school and asks the following,"How many times within the past school year have you been physically assaulted at school? She calculated the following ...

Stats
The average price for new mobile homes is known to be distributed with a standard deviation of 350. if a random rample of 49 homes resulted in a sample mean of 38500, obtain a 90% confidence interval on the population mean.

bus. stats
Given that math SAT scores are normally distributed (follow the empirical rule) m=500 Standard deviation=100 what is the math SAT score for someone who is in the 80th percentile of his or her class.

bus. stats
Given that math SAT scores are normally distributed (follow the empirical rule) m=500 Standard deviation=100 what is the math SAT score for someone who is in the 80th percentile of his or her class.

business research
The standard deviation of the sample is 0.4. Over the last 10 years, the average GPA has been 3.0. Is the GPA of this year’s students significantly different from the long-run average? At what alpha level would it be significant

Statistics
19. George got 70% on an economics exam where the mean was 55% and the variance was 9. If a professor wishes to change the distribution of marks so that they have a mean of 70% and a standard deviation of 5, what will George’s new mark be? a) 95% b) 85% c) 90% d) Over 100% ...

Quantitative methods
the mean and standard deviation of the grades of 500 students who took an maths exam were 69 and 7 respectively. if the grades have a bell shaped distribution, how many of these students received a grade of more than 83 marks?

Quantitative methods
the mean and standard deviation of the grades of 500 students who took an maths exam were 69 and 7 respectively. if the grades have a bell shaped distribution, how many of these students received a grade of more than 83 marks?

mathematical modeling
Use the 68-95-99.7 rule to solve: The amount of Jen's monthly phone bill is normally distributed with a mean of $48 and a standard deviation of $6. Fill in the blanks. 95% of her phone bills are between $_____ and $_____.

economics
the average tax charge is $95. Assuming a normal distribution as a standard deviation of $10, use the approximate areas beneath the normal curve to answer what proportion of tax prep fees were exactly $100?

statistics
Your samle is normally distributed with a mean age of 57. The standard deviation iin this sample is 5 years.The 2000 census shows your sample is older than a randomly selected national sample. The median agein your sample is?

Math IV
what is the margin of error for a simple random sample of 900 people with a standard deviation of 13.5 at 95% level of confidence How do you write this question in the right formula, please? I believe I can calculate the problem, I don't know how to write it. 900 2.5 and 1.96

Statistics
Below are the numbers of games played in the World Series from 1903 to 2012. Find the mean, variance and standard deviation. Games played Probability 4 0.186 5 0.231 6 0.203 7 0.341 8 0.039

MATH
A food snack manufacturer 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 0.15, find the 95% confidence interval of the true mean.

math
Adult IQ scores are normally distributed with mean 100 and standard deviation 15. Find the IQ score that separates the adults with the highest 3% of IQ scores from the rest of the adults. Round your answer to the nearest whole number.

stats
Using the following data set a. Calculate the mean, mode, median, standard deviation, minimum, maximum and range b. Draw the histogram of the data set. Use 100 as bin width

stats
Using the following data set a. Calculate the mean, mode, median, standard deviation, minimum, maximum and range. b. Draw the histogram of the data set. Use 100 as bin width.

Statistics
Suppose a fair coin is tossed five times and let x be the number that turned up in those five times. **the mean and the standard deviation are respectively... a.) 0.5, 0.5 b.) 2.5, 0.5 c.) 2.5, 2.24 d.) 2.5, 1.12 **find P(x≥1) a.) 0.5 b.) 1.0 c.) 0.03 d.) 0.97 * i just ...

Statistics
From a sample with n equals=24​, the mean number of televisions per household is 3 with a standard deviation of 1 television. Using​ Chebychev's Theorem, determine at least how many of the households have between 1 and 5 televisions.

Statistics
suppose that 80% of all 18 year olds play basketball. if a sample size of 4 is taken, find the probability that the sample proportion lies within and including one standard deviation of the population proportion

statistics
The mean rent of a 3-bedroom apartment in Orlando is $1200. You randomly select 12 apartments around town. The rents are normally distributed with a standard deviation of $75. What is the probability that the mean rent is more than $1000?

math
2 51 45 58 41 44 37 38 40 44 45 40 59 45 44 34 44 43 48 32 38 1.Determine the mean of the data 2.Determine the standard deviation of the data

ap statistics
What is the mean of the sample means? What is the standard deviation of the sample means?

ap statistics
What is the mean of the sample means? What is the standard deviation of the sample means?

Algebra
The mean is 18.1 the data set for 13 is -1.7 What is the standard deviation for this data set.

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?

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