STP
220 Final Exam Name: _________________
Spring,
2003
Fowler
Questions 1-12 are worth 5 points each. Circle your answers, or write your answers in the blanks provided. For all calculations, round to THREE decimal places.
1)
The
measure of uncertainty for a sample size of 100 is smaller for a population of
10,000 than a population of 1,000. True
or False?
2)
Which
is more important: Having a large
sample or a representative sample?
3)
The
probability that a person dies from a heart attack is 0.33. The probability that a person dies from
cancer is 0.20. Assuming that a person
can have only one cause of death, what is the probability that a person dies
from either a heart attack or cancer?
__________
4)
Suppose
the probability of winning a game is 0.38.
What is the probability of not winning the game? ___________
5)
Using
a smaller sample will result in a (circle one) wider or narrower
confidence interval than if a larger sample is used.
6)
Which
of these is more likely to give you a narrower confidence interval?
a)
Sample
Proportion ± MOE b) Sample Proportion ± 2 (s.d.)
7)
If
a “small” sample size is used, it becomes easier to reject the null hypothesis.
True or False?
8)
A
99% confidence interval is (circle one) wider or narrower than a
95% confidence interval.
9)
If
the null hypothesis is true, the p-value is the probability of making an error
by choosing the alternative hypothesis instead. True or False?
10)
Suppose
100 different researchers each did a study (using the conventional 5%
criterion) to see if there was a relationship between coffee consumption and
height. Suppose there really is no such
relationship in the population.
Approximately how many researchers would you expect to find a
statistically significant relationship simply by chance? __________
11)
For
any normal curve, approximately ______% of values fall within 1 standard
deviation of the mean in either direction
12)
Which
of the following do you think is more likely?
(check one)
o Getting heads at least twice
when tossing a coin three times
o Getting heads at least 200
times in 300 tosses
o Both are equally likely.
13)
(10
points) Amy reads a newspaper article
saying that the average GPA at ASU is 2.34.
She wants to test the validity of this information. She takes a random sample of 33 ASU students,
and asks them for their GPA. She finds
that the mean and standard deviation for her sample are 2.75 and 0.35
respectively. State the null and
alternative hypotheses for this test, find the p-value, and make a
decision. Show your work!!!
14)
(10
points) Researchers in England
collected data on the number of married couples in which the wife was taller
than the husband. Of the 200 randomly
selected households, there were 10 in which the wife was taller than the
husband. Construct a 95% confidence
interval for this proportion. Interpret
the meaning of this interval.
15)
(10
points) In Case Study 1.1, Lee Salk did
an experiment to see if hearing the sound of a human heartbeat would help
infants gain weight during the first few days of life. By comparing the weight gains for two sample
groups of infants, he concluded that it did.
One group listened to a heartbeat and the other did not.
- State the null and alternative
hypotheses for this study.
Use complete sentences!
- What would a type 1 error be for
this study?
Use complete sentences!
16)
(10
points) Use the contingency table below
to find the following:
The proportion that do not have the disease
= ______________
The proportion who test positive for the disease = ______________
The probability of a False Negative
=______________
Sensitivity =______________
Specificity =______________
|
|
Test + |
Test - |
Total |
|
Have |
95 |
5 |
100 |
|
Don’t Have |
9,890 |
90,010 |
99,900 |
|
Total |
9,985 |
90,015 |
100,000 |