Math 221 week 1 lecture nov 2012 with help

Week 1 LectureMA 221 Statistics for Decision Making

Professor Brent HeardNot to be copied or linked to without my permission

Week 1 Lecture MA 221

•Week 1 (Homework and Graded DB)•Week 2 (Homework, Graded DB and Lab)•Week 3 (Homework, Graded DB and Quiz)•Week 4 (Homework, Graded DB and Lab)•Week 5 (Homework, Graded DB and Quiz)•Week 6 (Homework, Graded DB and Lab)•Week 7 (Homework, Graded DB and Quiz)•Week 8 (Final Exam)


•Determine whether the data set is a population or a sample. Explain your reasoning.

The salaries of each teacher in a high school.


•Determine whether the bold value is a parameter or a statistic.

In a statewide survey on candy consumption, 72.7% of respondents between the ages of 40 and 49 reported M&M’s as a favorite candy.


•Determine whether the bold value is a parameter or a statistic.

In a study of all teachers in a particular high school, 98% own a cell phone.


•Determine whether the variable is qualitative or quantitative.

Enrollment of an elementary school.



Colors of cars in the parking lot of an office building.



Zip Codes of the students in your online class.


•What is the data set’s level of measurement?

Colors of cars in the parking lot of an office building.

Nominal



Daily low temperatures in Fahrenheit for December 2011.

Interval



Number of dogs each of your classmates have at home.

Ratio



College Football Rankings.

Ordinal


•Which method of data collection is described?

Asking every fifth student in line to enroll what they are planning on majoring in.

Systematic because they are asking every nth or 5th student in line



Looking at all 20 entry level statistics classes at a university and survey 2 students from each class.

Stratified because you have “20 classes” and you are selecting a specific number from each



Looking at all 20 entry level statistics classes at a university and surveying everyone in one of the classes chosen at random.

Cluster because I randomly chose one of the groups and surveyed ALL of them



Standing outside the local shopping mall and asking people what they think of the new mall 15 miles away.

Convenience sampling because we are just asking those that are convenient



Putting all of the first grade students names in a hat and drawing one to get to sit next to the teacher at lunch.

Random sampling because everyone or thing has an equal of chance of getting selected


•Describe whether you would take a census or use a sampling to collect data for the study described below.

The average salary of the 75 workers at a small business.

Census because you can easily get all 75


•Describe whether you would take a census or use a sampling to collect data for the study described below.

The average number of times per year the citizens of a 250,000 population city use the library.

Sample because of the large number


• For the Data:56 74 84 98 88 77 79 74 80 91The stem and leaf would be:5| 66|7| 44798| 0489| 18

Skewness

“Tail” to the Left “Tail” to the Right

Think of a “Bell”Or PerfectMountain

Think of a “Block of wood”



•Find the mean, median and mode for the following set of data representing the number of children a sample of 10 families have living at home. Explain what each measure of center is in plain language.

2 2 3 1 0 3 0 1 0 2

Mean = 1.4 Median = 1.5 Mode = 0 AND 2


•Find the range, mean, standard deviation for the following set of data representing the number of children a sample of 12 families have living at home. Know what the terms mean.

2 2 3 1 0 3 0 1 0 2 4 3

Range = 4 Mean = 1.75 Standard Deviation = 1.36

Week 1 Lecture MA 221• Average sales per customer at a Fast Food

Restaurant have a bell-shaped distribution with a mean of $5.37 and standard deviation of 78 cents. Using the empirical rule, give the following intervals.

• 68% of the values would fall between what two values ( 5.37 - .78, 5.37+ .78)

• 95% of the values would fall between what two values ( 5.37 - 2(.78), 5.37+ 2(.78))

• 99.7% of the values would fall between what two values ( 5.37 – 3(.78)), 5.37+ 3(.78))


•Explain all of the values associated with a box and whisker plot and what they mean.

MinMax

Median1st Quartile 3rd Quartile


•Explain what a z score of zero would mean. Then explain the difference between a positive and a negative z score.

A z score of zero is right on top of the mean. A negative z score is below the mean. A positive z score is above the mean. It’s that simple.

About MeI have worked in the NASA world since completing my graduate degree in 1987.

I earned both my M.S. and B.S. in Mathematics from Jacksonville State University in Jacksonville, Alabama. I did Post Graduate work in Mathematics and Engineering Management at the University of Alabama, Huntsville.

My teaching experience has included a number of colleges in Alabama and Virginia, as well as many years with DeVry. I am the live lecturer for all undergraduate and graduate statistics classes at DeVry.

In my spare time I enjoy writing. My genre is observational humor. In other words, I just enjoy finding humor in the world and making people laugh. My stories can be found in newspapers and at www.CranksMyTractor.com .

http://www.cranksmytractor.com/


•I sometimes post additional helps in my “Statcave” on Facebook

•You DO NOT have to be a Facebook person to see these, I simply post there for convenience and fun.

•Website: www.facebook.com/statcave

Math 221 week 1 lecture nov 2012 with help

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