Warm-up
An Exercise in Sampling: Rolling Down the River
1. What will the treatment be?
2. What will the response variable be?
3. How will the response variable be measured?
4. What will the experimental unit be?
5. Specify the experimental conditions to be used by
considering factors that might have ….what, if anything,
should be done to control this variation.
6. Skip this one…
4.3 E #25 – 26 a and b
25) a. There is radomization of the 10 plants there are split
into the 2 groups. There is replication. Five plants are getting
each of the treatments. There is a control group because 5
plants are replanted in their natural environment.
b. All ten plants need to be dug up so that confounding
variables such as sun/shade are not confounded by dug up
and not dug up.
26) a. The factors are powder and temperature. The levels are
the 2 types of powder and the 3 types of temperature. There
are 6 types of treatments.
b. The metallurgist should use randomization in and test only one
type of treatment at a time since there is only one oven. There
should also be an equal number of powders in randomly selected
areas of the oven.
4.3 # 26 c. and 27
c. This experiment could be blind if an assistant was the
one to randomly selected the powder for each of the 3
temperatures. The metallurgist could record the results.
27. The units in this experiment are the dormitories.
There are 20 dormitories. This is an experimental study.
Student of the day!
Block 4
Student of the day!
Block 5
Student of the day!
Block 6
Instructions for An Exercise in Sampling
Rolling Down the River
1) Answer all questions on a piece of paper in complete
sentences.
2) BEFORE answering questions, for Sampling Methods B,
C, D draw the 10 x 10 plot and explain how you used your
calculator to do the specified sampling. Also show the
results of the plots chosen using your method.
3) Also be sure to include the table with results
before the observation questions.
4) For Observation #4 we will be writing the results on the
board to the right of the classroom.
5) For Part II redraw the 10x10 plots describe your
methods briefly if you used the same methods.
A.P. Statistics Selected Ch. 3 Test Answers
5.
a. for the slope A, B, C was okay because
the residual plot had too much variation. But
the answers was really B.
c. Is the correlation coefficient a good
measure of association to use with the diameter versus age data?
Briefly explain your answer. In part b. most of you calculated it to be
0.9 and said the association was strong BUT there was a patter in the
residual so the correlation coefficient is not a good measure because
the relationship may not be linear or there may be a lurking variable.
6. For the function 0.735 ∙ year – 59.5; it was important to describe
slope as for every year younger the model of the car was the price
went up $735. Lost 1 of 2 pts if you were not specific enough.
A.P. Statistics
7.
a. Solve for
R2
SST  SSE
SS Re gression
r 

SST
SST
2
b. 67% of the variation in calories can be attributed to the
amount of fat.
Statistics Common Mistakes on Test
fuel consumption = –5465.5 + 15.50 · speed
 sy
b1  r 
 sx



5. a. A – C was fine. It was really B.
b. If the standard deviation of the fuel consumption is approximately
976.7 gal/h and the standard deviation of the speed is 54.8 mi/h, find
the correlation between fuel consumption and speed.
c. The residual plot had a pattern so the correlation coefficient,
although it is considered strong, it is not a good indicator of the
relationship between speed and fuel consumption. The U-shape of the
residual means that the relationship is not linear OR that there is a
lurking variable.
Statistics Common Mistakes on Test
8.
b.
SST  SSE
SS Re gression
r 

SST
SST
2
c. The R2 is the coefficient of determination which describes the
proportion of variation in the diameter that is determined by
age.
Be Ready for 4.1 to 4.3 Vocabulary Quiz Next Class
population, sample, sample size, sampling frame,
voluntary response bias, convenience sampling,
judgment samples, size bias, biased sampling
methods, unrepresentative sample, nonresponse bias,
questionnaire bias simple random sample, cluster
sample, probability sample, two-stage sample and
multistage sample, strata, stratified random sample,
lurking variable, confounding variable, experimental
study, observational study, control group, blind study,
double-blind study, experimental units, randomization of
treatment to subjects, replication, factors, levels, randomized
block design, replication
A.P. Statistics and Statistics H.W.
• For those teams that did not win the game, read
and define 4.3 and 4.4 terms.
• EVERYONE needs to complete up to #3 on Part 1
of the Rolling Down the River Activity
• EVERYONE should prepare for the 4.1 to 4.3
Vocabulary Quiz