Statistics And other Lies and Damned Lies The

Statistics And other Lies and Damned Lies

The Scientific Method

How many times do you see the letter F? Read the following sentence once and determine how many times you see the letter F.

How many times do you see the letter F? FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF MANY YEARS.

PRACTICE Use the following information to answer the next five exercises. Studies are often done by pharmaceutical companies to determine the effectiveness of a treatment program. Suppose that a new AIDS antibody drug is currently under study. It is given to patients once the AIDS symptoms have revealed themselves. Of interest is the average (mean) length of time in months patients live once they start the treatment. Two researchers each follow a different set of 40 patients with AIDS from the start of treatment until their deaths. The following data (in months) are collected. Researcher A: 3; 4; 11; 15; 16; 17; 22; 44; 37; 16; 14; 25; 15; 26; 27; 33; 29; 35; 44; 13; 21; 22; 10; 12; 8; 40; 32; 26; 27; 31; 34; 29; 17; 8; 24; 18; 47; 33; 34 Researcher B: 3; 14; 11; 5; 16; 17; 28; 41; 31; 18; 14; 26; 25; 21; 22; 31; 2; 35; 44; 23; 21; 16; 12; 18; 41; 22; 16; 25; 33; 34; 29; 13; 18; 24; 23; 42; 33; 29

PRACTICE Suppose that a new AIDS antibody drug is currently under study. It is given to patients once the AIDS symptoms have revealed themselves. Of interest is the average (mean) length of time in months patients live once they start the treatment. Two researchers each follow a different set of 40 patients with AIDS from the start of treatment until their deaths. Determine what the key terms refer to in the example for Researcher A. Population Sample Observational Units Parameter Statistic

Class Hours of Sleep

Distance to Skyline

Distance to Skyline

Distance vs. Time

Data and Variables Consider the students in this class as observational units. Classify each of the followingvariables as categorical or quantitative. If it is categorical, also indicate whether it is bin How long you have slept in the past 24 hours Whether or not you have slept for at least 7 hours in the past 24 hours How many states you have visited Handedness (which hand you write with) Day of the week on which you were born Whether or not you have used a cell phone so far today

Data and Variables Consider the students in this class as observational units. Classify each of the followingvariables as categorical or quantitative. If it is categorical, also indicate whether it is bin Whether you prefer baths or showers How much time you spent on your most recent bath or shower Whether or not you have a facebook account How many facebook friends you have

Data and Variables Is “average height” a legitimate variable, still considering you and your classmates as observational units? What about “percentage who have used a cell phone today”? Explain If you were to record the average student height, or the percentage of students who have used a cell phone today, for all classes taught at your school, would those be legitimate variables? What would the observational units be in this case?

Data and Variables What are the observational units in your time management study?

Variables of State Suppose that the observational units of interest are the fifty states. Identify which of the following are variables and which are not. Also classify the legitimate variables as categorical or quantitative. Gender of the state’s current governor Number of states that have a female governor Percentage of the state’s residents over 65 years of age Highest speed limit in the state

Variables of State Whether or not the state’s name contains one word Average income of an adult resident of the state How many states were settled before 1865 The number of states that you have been in Whether or not you have been in the state