Measures of Variability

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Questions

• How are the measures of central tendency and measures of dispersion complementary?
• Can the standard deviation be greater than the mean?
• Can the standard deviation ever be negative?
• What is the sample standard deviation formula?
• What is the symbol for the sample standard deviation?
• What are the symbols for the sample variance and for the population variance?
• Which data set has a larger standard deviation? First Data Set: 2, 4, 6, 8 Second Data Set: 12, 12, 12, 12
• If the standard deviation of a distribution is s = 7, what is its variance?
• Is the sample standard deviation "s" a resistant measure?
• How do you calculate the range of a data set?
• For the data set 6, 34, 12, and 14, what is the range?
• Why is the range of a data set seldom used in statistical analysis?
• What do the standard deviation and the range tell you about a data set, as contrasted to what the mean tells you?
• What is the difference between the population standard deviation and the sample standard deviation?
• Of the range and the standard deviation, which is more widely used in statistical analysis, and why?
• What does the standard deviation of a data set describe?
• If data with a normal distribution has a mean of 100 and a standard deviation of 15, what is the probability of a value being greater than 110?
• If data with a normal distribution has a mean of 100 and a standard deviation of 15, what is the probability that a given value is greater than 110?
• What is the standard deviation of #1, 2, 3, 4# and #5#?
• What is the standard deviation of {1, 2, 3, 4, 5}?
• What is the difference between the formulas for the standard deviation of a population and the standard deviation for a sample?
• What is the equation for standard deviation?
• What does a standard deviation of 0 indicate about a data set?
• A test consists of 910 true or false questions. If the student guesses on each question, what is the expected standard deviation of the number of correct answers?
• Why is standard deviation not a measure of central tendency ?
• What is the formula for the standard deviation of a binomial distribution?
• How can standard deviation be used in investment analysis?
• How does standard deviation differ from standard error?
• What does variance measure?
• What is the variance of the following numbers?: {4,7,4,2,1,4,5}
• What is the variance of 10 coin flips?
• What are the variance and standard deviation of a binomial distribution with #N=124# and #p=0.85#?
• What is the difference between the formula for variance and sample variance?
• What is the variance of the following numbers?: 11, 23, 45, 42, 39, 56, 51, 17, 22, 29, 46, 33, 38, 33, 31,
• What is the variance of the following numbers?: 63, 54, 62, 59, 52,
• What is the variance of the following set of numbers?: {40, 56, 59, 60, 60, 62, 65, 69, 75, 84}
• What is the variance of a geometric distribution for a given pobability?
• What is the variance of a geometric distribution for a given probability?
• How does the sample variance differ from the population variance?
• Why can't variance be negative?
• What is the difference between a sample and population variance?
• What is the mathematical formula for calculating the variance of a discrete random variable?
• What is the mathematical formula for the variance of a continuous random variable?
• What is the lower bound of a random variable's variance?
• If you are examining the height of a population, how would the variation be affected if everyone is wearing platform shoes that are exactly 3 inches tall?
• If you are examining the height of a population, how would the variance be affected if everyone is wearing platform shoes that are exactly 3 inches tall?
• What is the formula for the variance of a geometric distribution?
• What is the variance of X if it has the following probability density function?: f(x) = { 3x2 if -1 < x < 1; 0 otherwise}
• Why is variance invariant with regards to translation?
• If X and Y are uncorrelated variables, what is Var(X+Y) in terms of Var(X) and Var(Y)?
• How does the covariance between two variables affect the variance of their sum?
• How do you find the covariance of a continuous probability density function?
• How do you calculate the covariance between two discrete variables?
• If Corr(X,Y) = 0, does Cov(X,Y) = 0?
• What is a sample covariance?
• What is the difference between a correlation matrix and a covariance matrix?
• Is there a difference between a correlation and a correlation coefficient?
• What can covariance be used for?
• What is the relationship between standard deviation and variance?
• Is there any reason why the standard deviation is the square root of the variance?
• What does alpha and beta signify in portfolio analysis?
• Is covariance a measure of variability?
• If the median is 1900, the mean is 2144.58, and the sample standard deviation is 884.07, then what is the sample variance?
• What is the variance of z=2x+3y, in terms of the variances of x and y?
• If X and Y are correlated random variables, what is Var(XY)?
• What is population variance?
• What is sample variance?
• What is the variance of the following numbers?: {40; 56; 59; 60; 60; 62; 65; 69; 75; 84}
• What is the variance of the following probability distribution?: p(0)=0.05, p(2)= 0.17, p(4)= 0.43, p(6)= 0.35?
• What is the variance of the following numbers?: {2,9,3,2,7,7,12}
• What is the variance of the following numbers?: {3,5,2,2,4,7,8,5,7,12,6,4,}
• What is the variance of the following numbers?: {8,0,9,5,3,4,5,3,7,-5,3,6,8,4,3,}
• What is the variance of {3,6,7,8,9}?
• What is the standard deviation of {1, 2, 3, 4, 5, 6, 7}?
• How do you use a probability mass function to calculate the mean and variance of a discrete distribution?
• Suppose that X is a continuous random variable whose probability density function is given by: #f(x)= k(2x - x^2) for 0 < x < 2#; 0 for all other x. What is the value of k, P(X>1), E(X) and Var(X)?
• What is the variance of the following set of numbers?: {12, 19,19, 19, 20, 20, 21, 21, 21, 22, 22, 22, 22, 22, 22,23, 23, 23, 24, 25, 26, 26, 27, 27, 28, 32}
• John received a score of 75 on a math test where the mean was 50. If his score is 2.5 standard deviations away from the mean, what is the variance of the classes test scores?
• How do you determine the variance of a Poisson distribution?
• What is the mean and variance of a random variable with the following probability density function?: #f(x) = 3x^2 if -1 < x < 1#; 0 otherwise
• What is the variance of the following numbers?: {49, 49, 52, 53, 58, 62, 68, 75}
• What is the variance of {1000, 600, 800, 1000}?
• What is the variance of {15, 14, 13, 13, 12, 10, 7}?
• What is the variance of a probability distribution function of the form: #f(x)=ke^(-2x)#?
• If the following is a probability distribution function: #f(x)=k(e^(-x^2)+e^-x)#, what is #k# and what is the variance?
• If the following is a probability distribution function: #f(x)=k(1/x^2)#, what is k and what is the variance?
• If the median of a distribution is 1900, the mean is 2144.58, and the sample standard deviation is 884.07, what is the sample variance?
• What is the variance of {0, 26, 31, 36, 50}?
• What are the mean and standard deviation of {15, 9, 23, 12, 17}?
• What are the mean and standard deviation of {115, 89, 230, -12, 1700}?
• What are the mean and standard deviation of {34, 98, 20, -1200, -90}?
• What are the mean, median, mode, variance and standard deviation of {4,6,7,5,9,4,3,4}?
• What are the range, median, mean, and standard deviation of: {22, 12, 19, 24, 22, 21, 17, 14, 22, 20, 26, 10}?
• What are the range, median, mean, and standard deviation of: {212, 142, 169, 234, 292, 261, 147, 164, 272, -20, -26, -90, 1100}?
• What are the mean and standard deviation of {2,3,3,5,1,5,4,4,2,6}?
• What is the expected value and standard deviation of X if P(X=0) = 0.31, P(X-1) = 0.45, P(X=2) = 0.24?
• What is the expected value and standard deviation of X if P(X=0) = 0.76, P(X=1) = 0, P(X=2) = 0.24?
• What is the expected value and standard deviation of X if P(X=0) = 0.16, P(X=1) = 0.4, P(X=2) = 0.24, P(X=5)=0.2?
• If C is the union of A and B, how do you calculate the standard deviation of population C if you know the standard deviations of A and B? What if A and B are of different sizes?
• What is the variance of {40; 56; 59; 60; 60; 62; 65; 69; 75; 84}?
• What is the variance of {5, 5, 7, 25, 73, 89, 22, 1, 55, 93, 2}?
• What is the variance of {51, 3, 9, 15, 3, -9, 20, -1, 5, 3, 2}?
• What is the variance of {-7, 42, -5, 1, 6, -3, 4, -2, 17, 53, -2, 4, 7, 88}?
• What is the variance of {99, 4, 65, 12, -6, 21, 34, -52, 1, 83, -12, 44, 17, -8}?
• What are the variance and standard deviation of {2,9,3,2,7,7,12}?
• What are the variance and standard deviation of {8, 29, 57, 3, 8, 95, 7, 37, 5, 8}?
• What are the variance and standard deviation of {18, -9, -57, 30, 18, 5, 700, 7, 2, 1}?
• What are the variance and standard deviation of {1, -1, -0.5, 0.25, 2, 0.75, -1, 2, 0.5, 3}?
• What are the variance and standard deviation of {1, 1, 1, 1, 1, 80, 1, 1, 1, 1, 1, 1}?
• What are the variance and standard deviation of {1, 1, 1, 1, 1, 7000, 1, 1, 1, 1, 1, 1, 1, 1, 1}?
• How do I calculate the variance of {3,6,7,8,9}?
• What is the variance of {18, 19, 34, 38, 24, 18, 22, 51, 44, 14, 29}?
• What is the variance of {5, 3, 6, 14, 8, 10, 3, 17, 19, 9}?
• What is the variance of {-4, 5, 8 ,-1, 0 ,4 ,-12, 4}?
• What is the variance of {-2, 5, 18, -8, -10, 14, -12, 4}?
• What is the variance of {9, 4, -5, 7, 12, -8}?
• What is the variance of {-7, 12, 14, 8, -10, 0, 14}?
• What is the variance of {-5, 9, 7, 4, -15, 7, 18, -2}?
• What is the variance of {-4, 2, 3, 4, -15, 7, -8, -12}?
• What is the variance of {-13, 10, 8, -3, 6, 12, 7}?
• What is the variance of {15, 4, 2, -7, 8, 10}?
• What is the variance of {-6, 9, 10, 4, -7, 8, 11}?
• What is the variance of {-7, 8, -9, 10, 12, -14, 8}?
• What is the variance of {-4, 3, 12, 9, 10, -1, 0}?
• What is the variance of {-5, 19, -20, 5, 16, -7, 1}?
• What is the variance of {-3, 5, 4, -6, 15, -1, 20}?
• What is the variance of {17, 3, 10, 1, -3, 4, 19}?
• What is the variance of {7, 3, -1, 1, -3, 4, -2}?
• What is the variance of {8, 19, 10, 0, 1, 0}?
• What is the variance of {-4, 5, -7, 0, -1, 10}?
• What is the variance of {15, 9, -3, 8, 0}?
• What is the variance of {-4, 19, -3, 8, -10}?
• What is the variance of {9, -4, 7, 10, 3, -2}?
• What is the variance of {-3, -6, 7, 0, 3, -2}?
• What is the variance of {12, 6, 7, 0, 3, -12}?
• What is the variance of {12, 6, -2, 9, 5, -1}?
• Question #73fe5
• If 80% of the applicants are able to pass a driver's proficiency road test, how do you find the mean, variance, and standard deviation of the number of people who pass the test in a sample of 300 applicants?
• What is skewed distribution?
• What is the difference between variance and variability?
• How does an outlier affect the mean of a data set?
• Find the standard deviation of 36,45,14,18,20,24,28,33,47,55,51?
• What is the variance for the following data, 2 4 5 7 ? Please show working.[steps].