BIT chapter 4

It is possible to have a standard deviation of 440,000

True, it just has to be greater than or equal to zero bc it comes from a square root.

If the standard deviation of a data set is zero, then all entries in the data must equal zero.

False, if sd = 0, all entries are equal to the mean.

T or F It is possible to have a standard deviation of −3 for some data set.

False, standard deviation is avg distance and is computed from a sq. root, it cannot be negative.

T or F The population variance and sample variance are the same value for the same set of data.

False; the population variance and sample variance have different denominators in their formulas, so these values are almost always different.

Which of the following is true? a.The sum of the deviations is zero b. The sum of the square root of the deviations is zero c. The sum of the squares of the deviations is zero d. The sum of the absolute values of the deviations is zero

a.The sum of the deviations is zero

Amy is looking into investing a portion of her recent bonus into the stock market. While researching different companies, she discovers the following standard deviations of one year of daily stock closing prices. a. Garden Statues Express: Standard deviation of stock prices = $9.65 b. Masterful Pocketwatches: Standard deviation of stock prices = $1.05 Based on the data and assuming these trends continue, which company would give Amy a stable long-term investment?

b- smaller SD means less variability in closing prices, less risky

a value that is useful in comparing data values from populations with different means and standard deviations a. discrete variable b. standard deviation c. z score

c.

which of the following is true? a. population estimator is computed for data from a sample b. a population parameter is computed for data from a sample c. a point estimator is computed for data from a sample d. a point estimator is computed for data from the entire population

c. a point estimator is computed for data from a sample

Which of the following is true according to Chebyshev's theorem? a. at least 1/2 of the observations should fall within one standard dev. b. at least 5/6 of the observations should fall within three standard dev. c. at least 7/8 of the observations should fall within four standard dev. d. at least 3/4 of the observations should fall within two standard dev.

d. at least 3/4 of the observations should fall within two standard dev.

Z-score is also know as ... a. square of the standard deviation b. square root of the sample variance c. square of the mean d. standardized value

d. standardized value