Facebook Friends Activity
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Transcript of Facebook Friends Activity
What would the shape of the distribution of the number of friends be for all Facebook users?
What is your best guess for the average number of friends for all Facebook users?
What does Facebook
claim to be the
average number of
friends?
Is the claim from Facebooksignificantly different from your guess?
How could we determine if Facebook is right or not?
Hypothesis Test
Test whether the average number of friends is more than the Facebook claim with your own data.
H0:
Ha:
Randomly Choose Friends
Randomly Choose Friends
• Math > PRB > randInt(
• randInt(1, [max#friends], [2 to 10])
• Choose friends using random #s and record # of friends these friends have
How many friends do these three friends have? (Submit three separate numbers.)
Compile Data
Add data to L1
Assumptions
State assumptions and describe how each is satisfied.
1. Randomness
2. Normal population distribution
Histogram
2nd > STAT PLOT > ENTER
Highlight On and press ENTER
Type: histogram
xList: L1
Freq: 1
Zoom > 9
What is the shape?
Was your guess close?
Test Results
What is t?
t-Test
Stat > Tests > 2: T-Test…
Use the Data option
Mu0: 130
List: L1
Freq: 1
Mu: >Mu0
Calculate
Test Results
What is t?
What is p?
Test Results
What is t?
What is p?
Can we reject H0 and accept Ha? What is our official conclusion statement, then?
Test Results
What is the average number of Facebookfriends from our sample data?
Is it close to our initial guess?
Is it close to Facebook’sclaim?
What Now?
Should we email Facebook and let them know their stats are wrong?
What Now?
Should we email Facebookand let them know their stats are wrong?
What do they have that we don’t have?
Why might our numbers be different?
What assumptions might be erroneous in our sample?
Assumptions
Again, are the necessary assumptions satisfied?
1. Randomness
2. Normal population distribution