Module 1-6 SP-MATH-215

example of stratified sampling

A news reporter at a family amusement park asked a random sample of 20 kids and a random sample of 20 adults about their experience at the park.

relative frequency

A ratio that compares the frequency of each category to the total.

example of simple random sampling

A reality show assigns all qualified applicants a number and uses a random number generator to select the participant list.

convenience sampling

A sample that is not drawn by a well-defined random method is called a ____

x - a = # a - y = # Formula 1-1/k(squared) = ___%

If we do not assume that the histogram is bell-shaped at least what percentage of the sample values would be between __x__# and _y_#.

frequency

In a data set, the number of items that are in a particular category is called the

leaf

In a stem-and-leaf plot, the rightmost digit of each data value is the

example of a statistic

In a survey of 500 high-school students, 60% of them said that they intended to go to college.

time

In a time-series plot, the horizontal axis represents

example of ordinal

In the first round of the spelling bee, I came in second, but I came in first in the last round.

mean of random variable

Multiply each possible value by its probability, then add the products. example: 1(x)+2(x)+3(x)+4(x) = average

sampling with replacement

Once an element has been included in the sample, it is returned to the population. A previously selected element can be selected again and therefore may appear in the sample more than once.

multiplication rule for independent events

P(A and B) = P(A) x P(B)

General Addition Rule

P(A or B) = P(A) + P(B) - P(A and B)

Conditional Probability Formula

P(B|A) = P(A and B) / P(A)

non responders

People who are asked to participate in a study but refuse to do so are called

variance of binomial distribution

(n)(p)(1-p)

Conditions of a Binomial Distribution

- fixed number of trials -2 outcomes possible, success vs failure - probability of success must be the same for each trial - trials are independent - x represents the number of successes

five number summary

minimum, Q1, median, Q3, maximum

Conditional Probability

the probability that one event happens given that another event is already known to have happened

sample space

the set of all possible outcomes

binompdf(n,p,x)

this function on a calculator will produce the probability of an EXACT number of successes

binomcdf(n,p,x)

this function on a calculator will produce the probability of at most a number of successes examples: less than x greater than x fewer than x at least x

Bimodal

two peaks

quantitative

variables are always numerical

example of voluntary response sample

A caterer is choosing menu items for their next year. She sets up a free food tasting and asks people to critique the food.

example of systematic sampling

A football coach looks at his roster and asks every 8th player their opinion on a new logo

left

A histogram is skewed to the ____ if its left tail is longer than its right tail.

two standard deviation

95% of data will be within ____ of the mean

three standard deviations

99.7% of data will be within ____ of the mean

side-by-side bar graph

A bar graph that compares different groups, in one category, to one another.

Example of mutually exclusive

32 degrees in Orlando and 80 degrees in Orlando - two events that cannot happen at the same time

one standard deviation

68% of data will be within ____ of the mean

example of convenience sampling

A student artist selected all her recent pieces for the showing.

frequency distribution table

A table giving all possible values of a variable and their frequencies.

Outlier

A value that is considerably larger or smaller than most of the values in a data set is called

sampling without replacement

A variable of the population may be chosen for inclusion in a sample only once. If chosen, the variable is not returned to the population before the next selection.

example of cluster sampling

An electronics store randomly pulls the receipts from 20 different days over the past two years and calls all customers who purchased computers on those days to ask about high-speed Internet rates.

compound event

An event made up of two or more simple events.

an event

An outcome or collection of outcomes from a sample space is called

Use Avg(a) and Sx(s) Formula a - 1(s) = a+ 1 (s) =

Assume that a histogram for a sample is bell-shaped. Between what 2 values will approximately ___% of the sample be.

Use Avg(a) and Sx(s) Formula x-a = # a-y = # Divide output by Sx s/#

Assume that a histogram is bell shaped. What percentage of the sample values are between #x and #y

Use Avg(a) and Sx(s) x-a = b b/s = c from the standard deviation 95% = 5% on the outside 5/2 = 2.5%

Estimate the percentage of bills for which payment was made in greater than __x_ days.

Use Avg(a) and Sx(s)

Estimate the percentage of bills for which payment was made in less than 25 days.

mutually exclusive

Events that cannot occur at the same time.

68%

For a bell-shaped data set, approximately _____ of the data will be in the interval μ-σ to μ+σ.

75%

For any data set (including those that may not be normal), at least ____ of the data will be in the interval −μ-2σ to μ+2σ.

example of ordinal variable

I got an A in statistics, a B in biology, and C's in history and English.

nominal and ordinal

Qualitative variables can be divided into two types

Finding outliers

Subtract - Q3-Q1 = IQR Q3 + 1.5(IQR) UPPER BOUND Q1-1.5(IQR) LOWER BOUND

sample standard deviation

Sx

standard deviation

The _____ has the same units as the data

example of continuous

The amount of solar power to run landscaping lights.

variables

The characteristics of individuals about which we collect information are called

a sample space

The collection of all possible outcomes of a probability experiment is called

randomized experiment

a study in which the investigator assigns the treatments to the experimental units at random

IQR (interquartile range)

The quantity Q3-Q1 is known as the

variance

The standard deviation is the square root of the

1

The sum of all the probabilities in a discrete probability distribution must be equal to

one

The sum of all the probabilities in a discrete probability distribution must be equal to

independent

Two events are _____ if the occurrence of one does not affect the probability that the other event occurs

qualitative

Variables that classify individuals into categories are called

z-score

___ is the number of standard deviations from the mean

continious

____ random variables can take on any value in an interval.

discrete

____ variable is a quantitative variable whose possible values can be listed.

retrospective

_____ cohort study, subjects are sampled after the outcome has occurred

probability distribution

_____ for a discrete random variable specifies the probability for each possible value of the random variable (in chart form)

confounder

_____ is a variable related to both the treatment and the outcome.

stratified

_____ sample is one in which the population is divided into groups and a random sample is drawn from each group.

cluster

_____ sample is one in which the population is divided into groups and a random sample of groups is drawn

continuous

_____ variables can take on any value in some interval

Conveince Sample

______ sample - A representative of the student government association at a certain college stands at the door of the library and asks all students who enter about a new grading policy.

cohort study

______ study, a group of subjects is studied to determine whether various factors of interest are associated with an outcome.

simple random

_______ sample is a type of sample that is analogous to a lottery.

Histogram

a bar graph depicting a frequency distribution

horizontal bar graph

a bar graph in which the bars are read from left to right

discrete variable

a quantitative variable that has either a finite number of possible values or a countable number of possible values. NO DECIMAL AND NO FRACTIONS

unusual event

an event that has a low probability of occurring, typically less than .05

continuous random variables

are random variables that can take on any value in an interval ht, wt, distance

the law of large numbers

as a probability experiment is repeated again and again, the proportion of times that a given event occurs will approach its probability.

Finding the Midpoint

class range + class range / 2 ex. 1.0+1.9= 1.45

360

determining degree of pie chart by multiplying relative freq. by ____.

calculate relative frequency using

freq. of category/sum of freq.

times

frequency of a category is the number of ______ it appears in the data set

Pareto Chart

is a bar graph in which the bars are ordered by size

median

is a number that splits the data set in half.

pie chart

is represented by a circle in which the sizes of the sectors match the relative frequencies of the categories.

mode

is the value in the data set that appears most frequently

time series plot

is useful when the data consist of values measured at different points in time

observational study

observes individuals and measures variables of interest but does not attempt to influence the responses

Unimodal

one peak

social acceptability bias

people are reluctant to admit to behavior that may reflect negatively on them

finding percentile

percentile = 100 x (# of values less than x + 0.5)/# of values in the data set

continuous

random variables can take on any value in an interval.

one

relative frequency when added together should = ____

stratified

sample is one in which the population is divided into groups and a random sample is drawn from each group.

mean of a binomial distribution

μx = n * P

population standard deviation

σ

population variance

σ²

standard deviation of binomial distribution

√(np(1-p))