Standard Deviation from Expected Values

What is the last step in solving for standard deviation, according to Dr. Story?

• "Unsquaring" your SS

• "Unsquaring" the variance

• "Unsquaring" the deviation scores

• "Unsquaring" your degrees of freedom

For a distribution of scores with μ = 50 and X = 53, what is your deviation score?

• 0

• -3

• 1

• 3

Answer explanation

A deviation is a score's distance from the mean and uses the formula: X - μ. Using this formula, we should calculate 53 - 50 = 3.

Which of the following represents the amount of spread, dispersion, or variability of the items in a distribution?

• mean or expected value

• median and mode

• outcomes and probability distribution

• variance and standard deviation

How would you interpret a very small variance or standard deviation but not equal to zero?

• The values of the random variables are farther from the mean.

• The values of the random variables are nearer to the mean.

• The values of the random variables are equal to the mean.

• The values of the random variables have no relationship with the mean.

What formula is described by σ² = ∑[x² * P(x)] − u²?

Which of the following is NOT a property of the variance?

• The variance is not equal to the standard deviation.

• A small variance means that the distribution of the random variable is narrowly concentrated around the mean.

• A large variance means that the distribution is spread out, with some chance of observing values at some distance from the mean.

• The value of the variance is less than zero.

Which of the following rules state that almost all data fall within the 1, 2, and 3 Standard Deviation of the Mean when the population is normally distributed?

• Empirical rule

• Lottery rule

• Pascal’s triangle rule

• Sampling rule

Which of the following represents the mean value of a discrete random variable?

• Expected value

• Median

• Standard deviation

• Standard deviation

If one project has a higher standard deviation than another,

• it may have a lower risk

• it may have a lower expected value

• it has fewer possible outcomes

• it may be riskier, but this can only be determined by the coefficient of variation

The coefficient of variation (V) can be defined as the

• expected value multiplied by the standard deviation

• standard deviation divided by the mean (expected value)

• mean (expected value) divided by the standard deviation

• standard deviation squared, divided by the expected value