1 / 1.2 / 19.7
2 / 2.6 / 26.7
3 / 3.6 / 21.5
4 / 4.7 / 26.4
5 / 4.1 / 30.0
6 / 4.5 / 27.8
7 / 2.1 / 23.6
8 / 3.1 / 24.1
9 / 1.1 / 18.8
10 / 3.6 / 14.2
Regress the Crime Rate on the number of Police (data is fictional)
Calculate the residual for all the observations
Write out the regression line
Draw Regression Line to the graph below (& provide the two coordinates you used to plot the line)
Interpret the r & r2
Interpret b
If a city increases the police force by 1 per thousand, predict what will happen to crime
If a city has 3.0 police per 1,000, what would you predict the crime rate to be?
Interpret the Y intercept
Calculate the X intercept and interpret
Is this result expected? Can you think of a reasonable cause and effect relationship?
If a city wanted to get the crime rate down to 10 per thousand, how many police should they hire?
The delay in arrival (how late) of a commercial air flight is distributed normally with mean 8 minutes and standard deviation of 14 minutes.
Draw and calculate the probability of being more than 30 minutes late /
Draw and calculate the probability of being no more than 10 minute late
Draw and calculate the probability of a flight landing within 5 minutes of its scheduled time /
Your plane lands 20 minutes late, in what percentile is that?
Draw and calculate: Planes that land later than 80% of flights are how late? /
Draw and calculate: Planes that land earlier than 80% of flights are how early?
Draw and calculate: if an unusual event is one that happens less than 1% of the time, what would define an unusually early arrival? /
Draw and calculate: if an unusual event is one that happens less than 5% of the time, what times would define either an unusually early or late arrival?
Continuing with the airline example above, draw and calculate the probability of a flight being at least on-time.
Let this probability be the probability of “success”. If an airline is flying 60 flights, what is the probability of at least 30 being “on-time”.
New problem
The brewers of Schlitz beer develop a marketing ploy. Here’s what they know. Typical beer drinkers of brands like Miller, Bud, Michelob, Coors and Schlitz cannot tell the difference between the different brands of beer. This means if you have a taste-off with these types of beer drinkers, all the brands are equally likely to win as best for any given individual.
The makers of Schlitz had “Devoted Michelob” drinkers do a blind tasting of Michelob versus Schlitz during a Super Bowl. For anyone beer drinker, what is the probability that that drinker will prefer Schlitz?
Schlitz figures the promotion will be a success if at least 40% of the testers select Schlitz. If they let 10 people do the taste test, what is the probability of at least 40% preferring Schlitz?
If Schlitz has 100 people do the taste test, what is the probability of at least 40% preferring Schlitz?
How many people do you think Schlitz chose to use in the Super Bowl?
How would the statistics have been different if they used “Devoted Schlitz” drinkers instead of “Devoted Michelob”? Would this affect the promotion?