BStat unit 3

A set of measurements is divided into four parts, each containing approximately 25% of the measurements. These three dividers are called

quartiles

A z score has units interpreted as _____________ Multiple choice question.

standard deviations from the mean

The length of the interval that contains the middle 50% of measurements is known as ______.

the interquartile range

The interquartile range is the difference between which two quartiles?

first and third

Using Chebyshev's Theorem, at least 93.75% of the population measurements lie within _______ Standard deviations of the mean

four

For populations that are positively or negatively skewed, the empirical rule tends to ___

give unreliable descriptions of the distribution.

A data set has Q1 = 12 and Q3 = 20. Which measurements in the set { -2, 1, 30, 31} would be considered outliers?

-2

Standard deviation (the square root of variance) is expressed in _____ units as the original population.

the same

True or false: A box-and-whiskers display is a visual representation of the Five Number Summary.

true

A population value, x, has a z score of 3. What does this mean?

x is 3 standard deviations above the mean.

A data set has Q1 = 7 and Q3 = 11. Determine the lower and upper limits for a box plot.

1 and 17

Calculate the z score for the population value 8.2 where μ = 5.46 and σ = 2.37 (rounded to two decimals).

1.16

Fund X has a mean return of 12.43 percent with a standard deviation of 14.5 percent. What is the coefficient of variation for Fund X?

116.65

Fund Y has a mean return of 22.1 percent with a standard deviation of 3.73 percent. What is the coefficient of variation for Fund Y?

16.88

In a box-and-whiskers display, the lower whisker is drawn from ____ to _____.

Q1; the smallest measurement that is not outlying.

A sampling of prices for new and used houses found that the mean price for a new house is $120,000 and the standard deviation is $6100. It also found that the mean price for a used house is $50,000 and the standard deviation is $3150. Which of the following statements are true?

The coefficient of variation for used houses is 6.30% The coefficient of variation for new houses is 5.08%

Which of the following statements about population variance and standard deviation are true?

The more spread out the measurements in a data set are, the larger the variance will be. The raw deviations from the mean sum to zero. The more spread out the measurements in a data set are, the larger the standard deviation will be.

The coefficient of variation for Fund Z is 77.34. What does this mean?

The standard deviation is 77.34 percent of the mean.

Chebyshev's theorem states that for a population with a mean μ and standard deviation σ, ______ 100(1−1k2)1-1k2 percent of the population measurements lie in the interval [μ ± kσ]

at least

A ______ is a graphical summary of a data set's quartiles and interquartile range.

box-and-whiskers display

True or false: In the formula for calculating sample variance, the denominator is n (the sample size).

false

For a set of measurements arranged in increasing order, the pth percentile is a value such that p percent of the measurements are _____ the value. Multiple choice question.

less than or equal to

The empirical rule tends to give unreliable estimations when for populations that are:

positively & negatively skewed