Quiz: descriptive statistics 30 Q: 20 true/false 10 mc Q

A summary measure that is computed from a sample to describe a characteristic of the population is called?

a statistic

Which of the following reflect the need for statistical sampling?

all of the above

Those methods involving the collection, presentation, and characterization of a set of data in order to properly describe the various features of that set of data are called?

descriptive statistics

The process of using sample Statistics to draw conclusions about the true population Parameters is called?

inferential statistics

Which of the following statements about the standard deviation is true?

it is a measure of dispersion or variation

If outliers (extremely large or small numbers) are observed only among the highest values in a batch of data, the shape of the distribution of numbers

must be right (positively) skewed

A numerical measurement describing some characteristic of a population is called a ...

parameter

A contingency table (a two-way frequency table) is a table used to classify observations according to two different variables (characteristics) with the one variable identified in rows and the other in columns. ..."because the table shows how the individuals are distributed along each variable, contingent on the value of the other variable, such a table is called a contingency table."

True

A distribution of data that is zero skewed is symetrical?

True

An "outlier" is a data point (value) that is inconsistent with the rest of our data, and is often defined as a value that is more than 1.5 times the IQR (1.5 x IQR) larger than Q3 or smaller than Q1.

True

In a numerical batch of data the standard deviation can never be larger then the range?

True

In a numerical batch of data the value of "Q3" can never be smaller than the value of "Q1"?

True

The difference between Q3 (quartile 3) and Q1 (quartile 1) is referred to as the IQR (interquartile range) and is a measure of the middle 50% of our data.

True

The median is a measure of central tendency (or location)?

True

The relative frequency in each class of a relative frequency distribution is the frequency in each class of a frequency distribution divided by the total number of frequencies in the distribution?

True

The standard deviation is expressed in absolute terms (i.e. in the same unit of measure as the data: lbs;inches;dollars;etc) while the coefficient of variation is relative measure?

True

The sum of the differences between all the values in a numerical batch of data and their mean "balances out" to zero(i.e. If we subtract the mean from each value or observation in our data batchand add up all the differences will the sum of the differences sum up to zero?)

True

Three properties of data are "location", "dispersion", and "shape"?

True

A batch of numerical data can only have one mode?

False

A distribution of data that is positively skewed is left skewed?

False

If the mean is less than (smaller) the median, the data are positively skewed to the right?

False

The median of the values 3.4, 4.7, 1.9, 7.6, and 6.5 is 1.9?

False

The mode for the following values is "0"?...3.4, 4.7, 1.9, 7.6, 6.5.

False

The positioning point formula for the first quartile (Q1)in a data set is 3(n+1)/4?

False

The postioning point formula for the mode is (n+1)/2?

False

The variance is the square root of the standard deviation?

False

When using the summation notation, the symbol "S" tells us to add all values in the expression which follow it?

False

the shape of a distribution of numbers is given by the

skewness

A numerical measurement describing some characteristic of a sample is a ...

statistic

A score that tells us how many standard deviations a value is from the mean is a...μ

z-score