Statistics Test 1

There are ____________ quartiles and ___________percentiles in a data set.

3/99 (quartiles break into 4 equal parts, and percentiles break data into 100 equal parts)

The third quartile is a value in a ranked data set such that about

75% of the values are smaller and about 25% are larger than this value

Chebychev's theorem says that at least__________% of data falls within 2 standard deviations from the mean while the Empirical Rule states that approximately ________% will fall within 2 standard deviations from the mean.

75%/95%

A ______________ is a sample in which members of a population are selected based on the judgment and prior knowledge of an expert.

judgment sample

Which one of the following is a continuous variable?

lengths of top-ten hit songs (can assume any numerical value over a certain interval or intervals).

Which of the following summary measures is/are influenced by extreme values?

mean & range

Measures of central tendency are __________, ____________ and ____________.

mean, median & mode

The value of the middle term in a ranked data set is called the

median

Which of the following can have more than one value?

mode

Which of the following summary measures can be calculated for qualitative data?

mode

The values of the variance and standard deviation are

never negative

Which of the following is obtained by taking the difference between the largest and the smallest values of a data set?

range

Measures of dispersion are ___________, ______________ and _________________.

range, variance & standard deviation

A summary measure calculated for the sample data is called a

sample statistic

A box plot allows us to see which 3 characteristics for a data set:

skew, spread & symmetry

Standard deviation is always found by taking the ____________________________ of the variance. If we know the standard deviation but want the variance, we would ___________________the variance.

square root/square

A population in statistics means a collection of all

subjects or objects of interest

Under descriptive statistics, we study:

the methods for organizing, displaying, and describing data

An ______________ set contains information on each member of a sample or population individually

ungrouped data

A continuous variable is a variable that has:

values that exist over some interval.

When is the value of the standard deviation for a data set zero?

The value of the standard deviation is zero when all the values in a data set are the same.

The first quartile is a value in a ranked data set such that about

25% of the values are smaller and about 75% are larger than this value

For any number k greater than 1, at least (1−1/k2) of the data values lie within k standard deviations of the mean. Minimum Area Within k Standard Deviations 1.5 56% 2.0 75% 2.5 84% 3.0 89%

Chebyshev's Theorem

Chebyshev's theorem can be applied to

any distribution

A quantitative variable is the one that can:

assume numerical values

The empirical rule can be applied to

bell-shaped distributions only

A ______________ is a sample in which the most accessible members of the population are selected.

convenience sample

Data presented in the form of a frequency table are called ____________.

grouped data

Calculating Mean for Ungrouped Data

The mean for ungrouped data is obtained by dividing the sum of all values by the number of values in the data set. Thus, Mean for population data: μ=∑x/N Mean for sample data: x¯=∑x/n where ∑x is the sum of all values, N is the population size, n is the sample size, μ is the population mean, and x¯is the sample mean.

True/False: An ogive graph is always created using cumulative frequency or relative cumulative frequency for classes.___________________

True

A distribution curve that is right-skewed has:

a longer tail on the right side

For a bell-shaped distribution, approximately 1. 68% of the observations lie within one standard deviation of the mean. 2. 95% of the observations lie within two standard deviations of the mean. 3. 99.7% of the observations lie within three standard deviations of the mean.

Empirical Rule

True/Flase: An ogive graph is a type of bar graph or histogram________________

False, it's a line graph

Inferential statistics deal with:

Inferring something about a population based on sample data

Cross-sectional data are collected:

On different elements for the same period of time.

To create a pie chart, we must first find the _______________________________of each class or category. Next we would multiply this decimal by ___________in order to find the number of degrees for each piece of the pie.

Relative frequency/360

A summary measure calculated for the population data is called

a population parameter

Qualitative data can be considered_____________________________ while quantitative data is always ______________________.

non-numerical/numerical

A sample in which some members of the population may have no chance of being selected is called a

nonrandom sample

A sample in statistics means a portion of the

population of interest

Which of the following is the mean of the squared deviations of x values from the mean?

population variance

A parameter is a fact or characteristic for a ___________________while a statistics is a fact or characteristic for a ____________________.

population/sample

Measures of position are _____________, _______________, and ______________.

quartiles, percentiles & interquartile range

A _____________ is a sample selected in such a way that each group or subpopulation is represented in the sample in exactly the same proportion as in the target population

quota sample

A sample drawn in such a way that each element of the population has the same chance of being included in the sample is called a

random sample