Statistics

What are the questions they try to answer for descriptive statistics?

* What is a typical value for the measurements? How much variation do the measurements possess? * What is the shape or distribution of the measurements? * Are there any extreme values in the measurements and, if so, what does that tell us? * What is the relative position of a particular measurement in the group of data? * What kind of relationship exists, if any, when there are two variables and how strong is the relationship?

Scientific Method

A series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions.

Sample Statistic

Actual numerical descriptions of a particular sample characteristic

Class Width Equation

Class Width = Largest Value - Smallest Value / Number of Classes

Factors that influence the results of a study that the researcher did not, or could not, account for are known as ?

Confounding Variables

A company did a study on the physical activity level and weight gain of its employees. Age was not considered so it might be an example of a(n) .

Confounding variables

Heights of trees are an example of which type of data?

Continuous

When conducting a single-masked experiment a scientist should not apply a process to produce a desired response to the __?

Control Group

Continuous

Data that can take on any value within some interval

Discrete

Data that can take on values that are countable, such as 0,1 and 2 can only take particular values

Nominal Data

Data that represent whether a variable possesses some characteristic: values of the variables are names ex: the names of different people

59% of all freshmen at your school reside on campus Descriptive statistic or Inferential statistic?

Descriptive Statistic

62% of all students at the local university voted in the last election Descriptive statistic or inferential statistic?

Descriptive Statistic

Statics is divided into two categories:

Descriptive and Inferential

Inferential statistics

Develops theories to test the hypothesis using data collected from an experiment to make formal conclusions about a population or parameter

The numbers of languages that various people speak fluently are an example of which type of data?

Discrete

A car wash operator wants to study if using a new cleaning product will reduce staffing costs. Observational or Experimental?

Experimental

A coffee shop manager wants to know if providing a discount for local residents will generate additional revenue. Observational or Experimental?

Experimental

Statistic

Fact or characteristic about a sample

Population Parameter

Facts about the population, numerical description of a particular population characteristic Needs to describe all members being studied, not just a portion of them

Descriptive Statistics

Focuses on exploratory methods for examining data that yield the hypothesis mentioned in step two of the scientific method

Statistical Process Control(SPC)

Group of statistical methods designed to monitor and control processes

Ratio Data

Have a meaningful zero point and the ratio of two data points is meaningful estimate of the ratio between a magnitude of a continuous quantity and a unit magnitude of the same kind

Interval Data

If the data can be ordered and the arithmetic difference is meaningful distance between any two values has a specific meaning

Frame

List containing all members of the population

Qualitative Data

Measurements that can change in kind, but not in degree. Often consist of labels or descriptions and do not have naturally occurring numerical values. ways to categorize data Categorical data, gender, sex, quality, etc.

Quantitative Data

Measurements that change in magnitude from trial to trial such that some order or ranking can be applied. Can be measured using a naturally occurring numerical scale Numerical

What are the two ways to obtain data?

Observation and Controlled experiments

A gift shop owner wants to study the average age of his clientele. Observational or Experimental?

Observational

The heights of all the okra plants at Mr. Lonardo's greenhouse Population or Sample?

Population

65% of all students at the local university voted in the last election Population parameter or sample statistic?

Population Parameter

75% of all instructors at your school teach 2 or more classes Population Parameter or Sample Statistic?

Population Parameter

Types of motorcycles in a show room are an example of which type of data?

Qualitative

You toss a coin and record "head" as 1 and "tail" as 2. Qualitative or Quantitative? Discrete or Continuous? Highest level of measurement the data possesses?

Qualitative, neither, Nominal

Level of Measurement

Quality of data

Temperatures in degrees Kelvin of various sites on the moon are an example of which type of data?

Quantitative

The total weight of sugar imported by the United States each day for a year.

Quantitative, Continuous, Ratio

The IQ scores of students at the local college. Qualitative or Quantitative? Discrete or continuous? Highest level of measurement the data possesses?

Quantitative, Discrete, Interval

The number of French Fries in each of 40 individual servings Qualitative or Quantitative? Discrete or Continuous? Highest level of measurement the data possesses?

Quantitative, Discrete, Ratio

Ordinal Data

Represent categories that have some associated order involves collecting information on which the order is somehow significant ex: ranking or ordering on the basis of performance

The Midterm exam scores out of 6 of the 39 students in your math class population or sample?

Sample

The types of cars of a sample of 23 professors at the local college Population or sample?

Sample

A survey of 2345 people in the U.S. revealed that 75% of those surveyed eat while they drive Population Parameter or Sample Statistic?

Sample Statistic

A survey of 3740 people in the U.S. revealed that 76% of those surveyed work a full-time job Population Parameter or Sample Statistic?

Sample Statistic

Process

Series of actions that changes inputs to outputs

Population

Set of all subjects or elements about which we are interested in making inferences Particular group of interest

Bar chart

Simple graphical display in which the length of each bar corresponds to the number of observations in a category

If the nurses administering care know which participants received a placebo or treatment, but the participant does not have this information, the experiment is .

Single Blind

A research company believes teens today are getting less than the recommended hours of sleep. The company takes a list of 2000 teen volunteers and assigns each volunteer a number. A random number generator is used to select 350 individuals to take part in a sleep survey.

Single random sample

A research company believes teens today are getting less than the recommended hours of sleep. The company takes a list of 2000 teen volunteers and puts the teens into groups based on which area of the country they live in. The company randomly selects 50 teens from each region to take part in the sleep study.

Stratified random sample

Double Blind Studies

Subjects are not told whether they are members of the treatment group or the control group. The evaluators are also not told whether their subjects are members of the control or experimental group.

Sample

Subset of the population from which data is collected

Cumulative Frequency

Sum of the frequency of a particular class and all preceding classes

Census

Survey that includes all the elements or units in the frame

Descriptive Statistics

The collection, organization, analysis and presentation of data

Response Variable

The variable of interest in an experiment Ex: Students grades in physics course, SAT Scores

What is the objective of inferential Statistics

To make reasonable estimates about population characteristics using sample data

Controlled Experiment

To reveal the response of one variable (crop yield, the response variable) to changes in another variable (level of fertilization, the explanatory variable). In a controlled experiment the researcher attempts to control the environment of the experiment so that the effect of one variable one another can be isolated and measured

Explanatory Variable

Variable that affects the variable of interest (response variable) in an experiment Ex: Whether students take calculus before physics, SAT preparation course

Confounding Variable

Variable that was not controlled or accounted for by the researcher and thus damage the integrity of the experiment

How to find class boundary

add the upper limit of one class to the lower limit of the next class and divide by 2. For example, if an upper class limit is 10. and the next lower class limit is 11. 10+11/2=10.5

class width

difference between the lower limits or upper limits of two consecutive classes of a frequency distribution

If data or variables are quantitative, they can be further identified as ____

discrete or continous

upper class limit

largest number that can belong to a class

Observational data

measuring "what is".

Treatment group

plots containing the genetically engineered variety

Control group

plots containing the standard variety

Cumulative Relative Frequency

proportion of observations in a particular class and all preceding classes

lower class limit

smallest number that can belong to a particular class

class boundaries

split the difference in the gap between the upper limit of one class and the lower limit of the next class after finding the class boundary, add or subtract the class width to find the next class boundary.(usually given in interval form: lower boundary - upper boundary)

Frequency Distribution

summarizes data into classes and provides in tabular form a list of the classes along with the number of observations in each class

midpoint

the sum of the lower and upper limits of the class divided by two class midpoint = lower limit + upper limit / 2