y =b 0 +b 1x
b 1 =r
(xi - x ) 2
( x i - x ) ( yi - y )
( xi - x ) 2
i - x yi - y
( yi - yi ) 2
(n1 - 1) s 12 +(n2 - 1) s 22
(n1 - 1) +
9.1 (a) =2.5003 is a parameter (related to the population of all the ball bearings in the
container and x =2.5009 is a statistic (related to the sample of 100 ball bearings). (b) p =7.2%
is a statistic (related to the sample of registered vo
12.1 (a) 2.015. (b) 2.518.
12.2 (a) 2.145. (b) 0.688.
12.3 (a) 14. (b) 1.82 is between 1.761 ( p = 0.05) and 2.145 ( p = 0.025) . (c) The P-value is
between 0.025 and 0.05. (In fact, the P-value is 0.0451.) (d) t = 1.82 is signif
8.1 Not binomial: There is not fixed number of trials n (i.e., there is no definite upper limit on
the number of defects) and the different types of defects have different probabilities.
8.2 Yes: 1) Success means person says Yes an
1.1 (a) The sum of the weights is 231.8 million tons. (b) Bar graphs are shown below.
Percent of total
Percent of total
6.1 Answers will vary but examples are: (a) Flip the coin twice. Let HH represent a failure, and
let the other three outcomes, HT, TH, TT, represent a success. (b) Let 1, 2, and 3 represent a
success, and let 4 represent a failure.
U.S. Parents want Teachers Paid on Quality, Student Outcomes
This article talks about a survey that was taken on teacher compensation. There has
been much argument in the past about if teachers should be paid on a standard scale bas
11.1 (a) = the mean score for all older students at this college. (b) If = 115 , the sampling
distribution of x in Normal with mean 115 and standard deviation 30 25 = 6 or N(115, 6).
See the sketch below (on the left). (c) Assuming H 0 is t
15.1 The correlation is r = 0.994, and the least-squares linear regression equation is
y = 3.66 + 1.1969 x , where y = humerus length and x = femur length. The scatterplot with the
regression line below shows a strong, positive, linear rela
5.1 The population is (all) local businesses. The sample is the 73 businesses that return the
questionnaire, or the 150 businesses selected. The nonresponse rate is 51.3% = 77/150.
Note: The definition of sample makes it somewhat unclear whe
AP Statistics-Survey Project
Number of Extra-Curricular Activities vs. Hours of Sleep
We are studying the relationship between the number of extra-curricular activities
a student is involved in and the number of hours of sleep the student ge
3.1 (a) The amount of time a student spends studying is the explanatory variable and the grade
on the exam is the response variable. (b) Height is the explanatory variable and weight is the
response variable. (c) Inches of rain is t
7.1 (a) P(less than 3) = P(1 or 2) = 2/6 = 1/3. (b)(c) Answers will vary.
7.2 (a) The possible arrangements are: BBB, BBG, BGB, GBB, GGB, GBG, BGG, GGG. Each
arrangement has probability 1/8. (b) Three of the eight arrangements have