sample
a part of a population
outlier
a number that is very far from the other numbers in the set
median
the middle number in an ordered set of numbers
standard deviation
measures showing how much data values deviate from the mean
margin of error
helps you find the interval in which the mean of the population is likely to be, it's based on the size of the sample and the confidence level desired
conditional probability
the probability of an event B in relationship to an event A is the probability that even B occurs given that event A has already occurred
z score
the number of standard deviations that a value, x, is above or below the mean
binomial experiment
experiment that has a fixed number of trials, each trial is independent of the others, only two outcomes, and probability of each outcome remains constant from trial to trial
measures of central tendency
the mean, median, mode, and standard deviation of a set of data
standard normal curve
a "bell-shaped" curve for standard normal distribution
mean
the sum of the values in the set divided by the number of items in the set
range of a data set
the difference between the highest and lowest values in the set
mode
the value or values that occur most often in a set
confidence level
the percentage of all possible samples that can be expected to include the true population parameter
discrete data
data whose possible values are countable and often finite
continuous data
data which can take any numerical value within a range
sample
a subset of data selected from a population
population
all the possible data that are of interest in a study or survey
normal curve
a bell-shaped curve that is symetric about the mean of the data
normal distribution
a normal curve that is symmetrical about the mean of the data
mean
the average of the set of data for a population
standard deviation
a measure of how spread out the data are from the mean
standard normal distribution
a normal distribution with a mean value of 0 and a standard deviation of 1s
Emperical Formula for Normal Distributions
1. Approximately 68% of the data in a normal distribution for a population is within 1 standard deviation of the mean.
2. Approximately 95% of the data in a normal distribution for a population is within 2 standard deviations of the mean.
3. Approximately
z-score
a number that describes a specific data value's distance from the mean in terms of standard deviation units
percentile
a data value for which a certain percentage of the data is below the data value in a normal distribution
proportion
the relative frequency of a category
categorical
eye color or political affiliation
numerical
heights or salaries
cluster sample
population is divided into groups, some of the groups are randomly selected
stratified sample
the population is divided into groups, and individuals from each group are selected
systematic sample
members of the sample are chosen according to a rule, such as every nth individual in the population
convenience sample
individuals are selected based on how accessible they are
distribution
organizing the data values by using the frequency with which they occur results in a _______ of the data
Bee
Free
Bee
Free
Bee
Free
uniform distribution
a distribution whose shape is basically level (that is, it looks like a rectangle)
normal distribution
a distribution that is mounded in the middle with symmetric "tails" at each end (that is, it looks bell - shaped)
skewed distribution
a distribution that is mounded but not symmetric because on "tail" is much longer than the other
Binomial Experiment
experiment involves repeated trials where each trial has only two outcomes: success or failure
binomial probability of r successes in n trials
p(x=r) = n(rp^rq^n-r)
random variable
a variable whose value is determined by the outcome of a probability experiment
probability distribution
a data distribution that gives the probabilities of the values of a random variable
cumulative probability
the probability that a random variable is less than or equal to a given value
standard normal distribution
has a mean of 0 and a standard deviation of 1
z-score
z = x-M/standard deviation
Mean
M = Mu = ______
standard deviation
sigma = ______ ______
68-95-99.7 rule
a shorthand used to remember the percentage of values that lie within a band around the mean in a normal distribution with a width of one, two and three standard deviations, respectively; more accurately, 68.27%, 95.45% and 99.73% of the values lie within