ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos

AP Statistics 2.1 Statistical Inference 27 Views

Share It!

Description:

Want to pull an Oliver Twist and ask us for more? We've gotcha covered. Head over to /video/subjects/math/test-prep/ap-statistics/ for more AP Statistics goodness. No porridge included.

Language:

English Language

Subjects:

Tags:

Sampling And Experimentation / Generalizability of Results and Conclusions

Transcript

00:04
And here's your shmoop du jour brought to you by eye
00:06
drops keeping finish line photographers in business since 1945..Your principal [man photographs the end of a horse race]
00:12
wants to know the difference in lateness between students who ride their bikes to
00:16
school and those who drive there, if a confidence interval contains two
00:20
positive numbers what does this information mean for your principal and

00:24
here the potential answers.. Okay in other words who
00:32
causes that five minutes after the bell stampede every morning? Is it the sweaty [Students scramble into the school as alarm bell rings]
00:37
two wheelers, or the amateur NASCAR drivers in the parking lot well to get the answer [Motorbike and car arrive at school and students appear]
00:41
the principal has hired a statistician who proceeded to calculate a 95%
00:45
confidence interval that percentage is for the difference between
00:49
the proportion of bike riders who were late and the proportion of car drivers [person riding a bike and a car ride past the principal]
00:54
who were late...So besides being curious about what they're serving in the
00:59
cafeteria for lunch what else does the guy with the clipboard need to know [Man holding a clipboard in the school corridor]
01:02
nothing.. exactly, he has what he needs there's no missing link here people stay
01:08
with us for a second since the confidence interval was given we don't [Student discussing sample size at the front of the class]
01:11
need sample sizes an actual proportion so we can eliminate C and D as possible
01:16
answers we're comparing bike riders to car drivers and those positive numbers in
01:20
the confidence interval indicates that bike riders are late more than car [Bike and car appear]
01:24
drivers which means that A is the correct answer the only other conclusion
01:29
to be made from this exercise is that there are more bike riders than car [Students holding bike helmets outside the principal's office]
01:32
drivers waiting outside the principal's office..no one ever said confidence
01:36
intervals were fair.
Full Transcript