# Statistics

Submitted By kristendai913
Words 2677
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COMM 291
Midterm Review Package
Prepared by Angelica Cabrera

1. INTRODUCTION TO DATA AND VARIABLES Categorical vs. Quantitative Data Categorical Limited number – distinct categories No Quantitative Large number Yes

Possible values for variable Measurement units?

EXAMPLE. Which variables are quantitative and which are categorical? Employee # Age (years) Annual Income (in Performance 1,000s of dollars) Rating (1-5 scale) 5543 48 50 – 100 4.5 2431 34 20 – 49 3.9 7281 31 0 – 19 3.4

Job Type Management Clerical Maintenance

2. SURVEYS AND SAMPLING Population: _______ individuals with a common characteristic that you want to generalize about Parameter: fact or characteristic about _____________ Sample: ________ of population

Statistic: fact or characteristic about ______________

EXAMPLE. Mattel claims that less than 5% of all its Hot Wheels toys are defective. When testing 100 Hot Wheels toys from a production run of 7000 toys, 7% were found to be defective. What is the: a) Population? c) Parameter? Poor (Biased) Sampling   Convenience sampling: Choosing respondents that are __________ to obtain Voluntary response: Respondents volunteer, so those with __________ opinions are more likely to respond b) Statistic? d) Sample?

Sampling Designs 1. Simple Random Sampling (SRS): Every individual has an equal chance of being selected 2. Stratified Random Sampling: Divide population into ______________ subgroups and randomly select from each stratum 3. Cluster Random Sampling: Divide population into ______________ subgroups that are representative of population and select a few clusters 4. Systematic Sampling: with a random starting point, select at regular intervals

COMM 291 Review Package prepared by Angelica Cabrera

1

EXAMPLE. You are considering ways to randomly sample UBC varsity athletes to learn about types of sports drinks they would...

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