WEEK 3 QUIZ REVIEW FOR

MATH 221B. Heard

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Students may download one copy for personal use.)

WEEK 3 QUIZ REVIEW Data Collection

Understand and distinguish between Sampling Census Experiments Simulations Etc.

WEEK 3 QUIZ REVIEW Descriptive & Inferential Statistics

Know the differenceDescriptive - This is a set of methods to

describe data that we have collected. Inferential - This is a set of methods used to

make a generalization, estimate, prediction or decision.

WEEK 3 QUIZ REVIEW Know the difference between Qualitative

and Quantitative Data

WEEK 3 QUIZ REVIEW Types of Sampling

RandomStratifiedClusterSystematicConvenience

WEEK 3 QUIZ REVIEW Populations and Samples

Parameters and Statistics

WEEK 3 QUIZ REVIEW Standard Deviation and Variance

How to calculate and mathematical relationship.

Variance is the Standard Deviation squared.Standard Deviation is the square root of the

Variance.For example if you are given the standard

deviation is “3” and asked what the variance is, you would note it as “9” because 3^2 is 9.

If you were given the variance as 4.7 and asked for the standard deviation, you would note it as “2.17” because √4.7 = 2.17

WEEK 3 QUIZ REVIEW Be able to get a regression equation. Example

Data (4, 30), (4,35), (5,36), (6,42), (8,48)

WEEK 3 QUIZ REVIEW Be able to get a regression equation. Example

Data (4, 30), (4,35), (5,36), (6,42), (8,48)

WEEK 3 QUIZ REVIEW Be able to get a regression equation. Example

Data (4, 30), (4,35), (5,36), (6,42), (8,48)

WEEK 3 QUIZ REVIEW Be able to get a regression equation. Example

Data (4, 30), (4,35), (5,36), (6,42), (8,48)

This would be written as y = 3.982x + 16.70

WEEK 3 QUIZ REVIEW Use a multiple regression equation.• “Plug and Chug” (Plug in the values and

chug out the answer)• Exampley = -6.5 +12a + 5.1b where “a” is a

vocabulary score and “b” is a skills test score. y predicts the person’s score on a job performance test.

Predict a job test score for a person who made a 50 as a vocabulary score and got a 7 as a skills test .

y = -6.5 +12(50) + 5.1 (7)y = 629.2

WEEK 3 QUIZ REVIEW Correlation Coefficients, also noted as

“r”• Range from -1 to +1• .75 to 1 is strong• .5 to .75 is moderate• .25 to .5 is weak• 0 to .25 is almost none, I would probably

note it is as “NO CORRELATION”• + would be positive correlation, - would be

negative correlation• For example, -0.58 would be moderate

negative correlation

WEEK 3 QUIZ REVIEWFrom Page 487 in our text

WEEK 3 QUIZ REVIEW Be able to create a stem and leaf plot

Use Minitab!

Determine descriptive statistics.• Mean, Median, Mode, Range, Variance,

Standard Deviation Use Minitab!

WEEK 3 QUIZ REVIEW Identify Class Width Identify Midpoint of certain classes Identify class boundaries Give the relative frequency Fishing Tournament Data below is an example

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

WEEK 3 QUIZ REVIEW Class Width is 8

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

8-0 = 8, or you could havesaid 15 – 7 = 8, or counton your fingers, 0,1,2,3,4,5,6,7(There are eight numbers,don’t let it fool you)

IT is “8” Not 7!

WEEK 3 QUIZ REVIEW Midpoint of second class is 11.5

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

8+15 = 23 divided by 2 gives you 11.5

WEEK 3 QUIZ REVIEW What are the class boundaries of the third class?

15.5 and 23.5

Number of Fish Frequency0-7 9

8-15 1516-23 1224-31 3

Subtract .5 from the lower to get 15.5 and add .5 to the upper to get 23.5

WEEK 3 QUIZ REVIEW Give the relative frequency of all classes

Number of Fish Frequency Relative Frequency0-7 9 9/39

8-15 15 15/3916-23 12 12/3924-31 3 3/39

Total of 39

Total your Frequency column, the total is your denominator for your fractional relative frequencies. You could also have noted these in decimal form.

WEEK 3 QUIZ REVIEW Come see me at the “Statcave” www.facebook.com/statcave You DO NOT have to be a Facebook

person to see these. If you are, become a fan. IT IS NOT REQUIRED TO BE ON

FACEBOOK. IT’S SOMETHING I DO FOR FUN.

I often post helpful things there for fun and you can look at old posts that may be helpful.