Stat 240 Exam 1 Key
1.
About 68% will fall in the interval 76 8, or 68 to 84
About 95% will fall in the interval 76 (2)(8), or 60 to 92
About 99.7% will fall in the interval 76 (3)(8), or 52 to 100
2. Slope =5. Average weight increases 5 pounds per each o
STAT 240 EXAM 2 Study Guide Penn State
normal distribution:
a theoretical frequency distribution represented by a normal
curve
Carl Friedrich Gauss:
the theoretical curve that describes the normal distribution has
been referred to as a bell shaped curve o
STAT 240 Quiz 6 KEY
1. In a national survey conducted in 2000, the National Opinion Research Center asked a random sample
of 1,780 adults whether they favored or opposed the legalization of marijuana. A total of 1,183, or
roughly 65.5%, of the respondents
Stat 240 Quiz 5 KEY Answers underlined and in bold.
Which of the following examples involves paired data? (Only one choice is correct)
A.
A psychologist compares two methods of memorizing information. Twenty people use one method
and twenty other people u
STAT 240 QUIZ 4 KEY Answers are underlined and in bold
1. Which statement about confidence intervals is FALSE?
A. A confidence interval is an interval of values computed from sample data that is likely to include
the true population value.
B. An approxima
Stat 240 Quiz 3 KEY answers underlined and in bold
Questions 1-3 The distribution of systolic blood pressures within a certain age group looks like
a bell curve. The mean value is 120 and the standard deviation is 10. NOTE Below there is a
table of cumula
Stat 240 Quiz 2
Fall 2003
Sept. 22, 2003
1. Which of the following correlation values indicates the strongest linear relationship between two quantitative
variables?
A. r = 0.65
B. r = 0.30
C. r = 0.00
D. r = 0.50
-Questions 2 to 5: A group of adults aged
Stat 240 Fall 2003 Quiz 1 Sept. 10
Questions 1 and 2 refer to the following statistical summary of the number of CDs owned as
reported by n = 250 students in a class survey done at Penn State University.
Variable
N
Mean Minimum
Q1
Median
Q3
Maximum
CDs
25
Homework 8 Key
Problem 1
a. H0: = 98.6
b. H0: p1 p2 = 0
c. H0: d = 0
d. H0: 1 2= 0
Ha: < 98.6
Ha: p1 p2 >0
Ha: d > 0
Ha: 1 2 0
Minitab: 1-sample t
Minitab: 2-proportions
Minitab: Paired t
Minitab: 2-sample t
Problem 2
a. Confidence interval
b. Significanc
Stat 240 Homework 7 Key
2
=
= 0.25 cm. Over all possible samples of n = 64 from this population, the
n
64
average difference between the sample mean and the population mean is about 0.25 cm.
b. The interval is 27 to 28 cm, computed as 27.5 2 0.25.
Calcula
Stat 240 Homework 6 Key
11.6
11.12
11.24
11.25
11.27
Ho: p = .65
(same as standard)
Ha: p > .65
(better than standard)
The null hypothesis could also be written as Ho: p .65.
a. The woman is not pregnant.
b. The woman is pregnant.
c. She is not pregnant.
Stat 240 Homework 5 Key
9.17
9.18
10.11
a. Mean = p = .2
.2(1 .2)
b. s.d. ( p ) =
= .05 .
64
c. .15 and .25, calculated as .2 .05.
d. .10 and .30, calculated as .2 (2 .05).
.70(1 .70)
a. Mean = .70; s.d. ( p ) =
= .0324 .
200
b. .70 (3 .0324), or .6028 to
Homework 1 Key
2.54
a. Mean St. Dev is 7 1.7, or 5.3 to 8.7.
b. Mean 2 St. Dev is 7 (2)(1.7), or 3.6 to 10.4.
2.55
Figure for Exercise 2.55
z = (200170)/20 = 1.5.
z = (140170)/20 = 1.5.
z = (170170)/20 = 0.
z = (230170)/20 = 3.
2.56
a.
b.
c.
d.
2.57
a. Me
Stat 240 Exam 3
Key
(90 point total, show your work = 26, multiple choice = 64)
Question 1, each part 2 points
A. 10 = paired t-interval; we have paired data (befor, after), we want know how much, were
looking at a mean.
B. 7 = 2-proportions test; we have
Stat 240 Exam 3
Name _
1. For each part of this question, identify the statistical procedure that can be used to
answer the research question. Give the number and/or name of your choice using the
following numbered list of choices.
Analysis Choices
5. 2-s
Stat 240 Exam 2 Key and Results
Show Your Work Key:
(5 pts) 1. type 1 = deciding new treatment is better when actually it is not
type 2 = deciding new treatment is not better when actually it is
(7 pts) 2. A. z = (7165)/8 = 0.75. Look up z = 0.75 in table
STAT 240 EXAM 3 Study Guide Penn State
hypothesis testing:
a method used in statistics to test a hypothesis using a null
hypothesis
alternative hypothesis:
the hypothesis one is trying to support when they test and
hopefully reject the null hypothesis
res