Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/45

Click to flip

45 Cards in this Set

  • Front
  • Back
measures of central tendency
also called measures of average

mean
median
mode
midrange
measures of variation
also called measures of dispersion

range
variance
standard deviation
measures of position
used extensively in psychology and education, norms

percentiles
deciles
quartiles
parameters
a characteristic or measurement obtained by using all data for a population
statistic
a characteristic or measure obtained using data values from a sample
what is the general rounding rule?
rounding should not be done until the final answer is calculated
mean
formula
also known as the arithmic average

add all values then divide by the number of values
mean
also known as the arithmic average

add all values then divide by the number of values
rounding rule for the mean
the mean should be rounded to one more decimal place than occurs in the raw data
median
the midpoint of the data array
data array
ordered data

1 2 3 4 5

12 23 32 44 51
mode
the value that occurs most often in a data set

there can be one, none, or multiple modes

a data set w/ multiple modes is bimodal
the modal class
the class with the largest frequency
midrange
formula
a rough estimate of the middle

(lowest value + highest value) / 2
midrange
formula
a rough estimate of the middle

(lowest value + highest value) / 2
weighted mean
formula
used when values are not equally represented

multiple each value by its corresponding weight, divide the sum of products by the sum of weights
which varies less,

mean, median or mode?
mean varies the least of these
Can a mean be computed for an open ended frequency distribution?
no
what are outliers?
extremely high or low values that can affect the accuracy of the mean and the midrange
can the median be used for open ended distributions?
yes
positively skewed distribution
right skewed tail to the right
symmetric distribution
data is evenly distributed on both sides of the mean
negatively skewed
left skewed, tail to the left
measurements for the spread of variability
range
variance
standard deviation
rounding rule for standard deviation
final answer should be rounded to one more decimal place that the original data
variance
formula
is the average of the squares of the distance each value is away from the mean

subtract the mean from each value, square each difference, add all squared differences, divide the sum of squared differences by the population size
the larger the variance or standard deviation,...
the more variable the data
the symbol for sample size is
n
the symbol for an individual value is
x
the symbol for range is
R
how do you find the standard deviation?
take the square root of the variance
the symbol for the population standard deviation is
ó
the symbol for the population standard deviation is
ó
the symbol for population mean is
µ
the symbol for sample mean is
X (with a bar above it)
the symbol for a sample standard deviation is
s
Chebyshev's theorem states that for any distribution___________________ of the data will fall within 2 standard deviations of the mean.
75%
coefficient of variation formula
standard deviation divided by the mean and expressed a percentage
symbol for coefficient of variation
CVar
the empirical rule
these are true with a normal distribution
1)appr. 68% of data values will fall within 1 standard deviation of the mean

2) 95% will fall within 2
3) 99.7% will fall within 3
z score
formula
also called standard score

the number of standard deviations a number is from the mean

(value-mean)/ standard deviation
percentile
formula
[(number of values below x)+ .5] /total # of values, given as a percentage
deciles
divide the distribution into 10 groups
find outliers
Q1-[(Q3-Q1)*1.5]

and

Q3+[(Q3-Q1)*1.5]
interquartile range
Q3-Q1