Download 3rd 9 weeks Review

1. Which of the following is NOT true of the 2
probability density function?
a) For small degrees of freedom, the curve displays
right-skewness.
b) As the degrees of freedom increase, the curve
approaches a normal curve.
c) 2 is defined only for positive values of the variable.
d) The area under a 2 curve is 1.
e) All of these are true about the 2 probability density
function.
2) A regression of the amount of calories in a serving of breakfast cereal
vs. the amount of fat gave the following results:
Calories = 97.1053 + 9.6525 Fat.
Which of the following is a FALSE statement?
a. It is estimated that for every additional gram of fat in the cereal, the
number of calories increases by about 9.
b. It is estimated that in cereals with no fat, the total amount of calories is
about 97.
c. If a cereal has 2 g of fat, then it is estimated that the total number of
calories is about 115.
d. If a cereal has about 145 calories, then this equation indicates that it
has about 5 grams of fat.
e. One cereal has 140 calories and 5 g of fat. Its residual is about 5 cal.
The two-way table specifies favorite ice cream flavors by gender.
Chocolate
Vanilla
Strawberry
Male
32
14
3
Female
16
4
10
3. A 2 test of significance yields a test statistic of 2 = 10.71 and a
p-value of .005 with df = 2.
Which of the following is a valid conclusion from this information?
a) We have sufficient evidence of an association between gender and
ice cream flavor preference at the 5% level.
b) There is insufficient evidence of a relationship between gender and
ice cream flavor preference.
c) Since we are dealing with the two genders, a two-sample t-test is
more appropriate.
d) No conclusion, since a 2 test should not have been preformed
due to assumption violations.
e) The information given is not sufficient to draw a conclusion.
4. A genetic model for offspring of two Labrador retrievers
states:
black: yellow: chocolate = 5:4:1.
Two Labrador retrievers are bred and a litter consisting of
3 black dogs, 5 yellow dogs, and 2 chocolate dogs is
produced.
For a goodness of fit test, the 2 statistic would be:
a) 1.79
b) 2.05
d) 4.94
e) 7.08
c) 2.92
5. An experimenter plants half of each of six flowerbeds with a new hybrid flower seed
and the other half of each with the standard seed. Each bed is given the same amount
of water and fertilizer. At the end of one week, the number of sprouts is counted and
compared. Which of the following tests would be most appropriate in establishing a
difference in the two seeds?
a) t-test of means
b) two-sample proportion z-test
c) matched-pair t-test
d) two-sample proportion t-test
e) chi-square test
6) The corn rootworm is a pest that can cause significant damage to corn,
resulting in a reduction in yield and thus in farm income. A farmer will examine a
random sample of plants from a field in order to decide whether or not the number
of corn rootworms in the whole field is at a dangerous level. If the farmer
concludes that it is, the field will be treated. The farmer is testing the null
hypothesis that the number of corn rootworms is not at a dangerous level against
the alternative hypothesis that the number is at a dangerous level. Suppose that
the number of corn rootworms in the whole field actually is at a dangerous level.
Which of the following is equal to the power of the test?
(A) The probability that the farmer will decide to treat the field.
(B) The probability that the farmer will decide not to treat the field.
(C) The probability that the farmer will fail to reject the null hypothesis.
(D) The probability that the farmer will reject the alternative hypothesis.
(E) The probability that the farmer will not get a statistically significant result.
The following table displays by gender the number of people in a
club who favor a particular political party.
Democratic
Republican
Independent
Female
20
35
45
Male
30
25
50
7. If we were to do a chi-square test, which expression would
calculate correctly the expected frequency of the number of
females who favor the Republican Party?
60  100
205
b) 35  60
105
d) 35  205
100
e) 35  100
205
a)
c)
60  100
105
The following table displays by gender the number of people in a
club who favor a particular political party.
Democratic
Republican
Independent
Female
20
35
45
Male
30
25
50
8. What is the probability that a person chosen at random will be
female given the person favors the Democratic Party?
a) 0.4
b) 0.2
d) 0.2439
e) 0.4878
c) 0.0976
9. We randomly sampled high school students from NY City and a group
from San Antonio. When comparing the ethnic diversity of student
populations, which of the following test would be best?
a) one proportion z-test
b) two-sample proportion z-test
c) chi-square goodness-of-fit test
d) chi-square test of homogeneity
e) chi-square test of independence
10. A test of independence for data organized in a two-way table relating
number of siblings and number of family relocations is conducted using
the chi-square distribution. The p-value of the test is .045. If alpha is .05,
then which of the following is a valid conclusion of the test?
a) The mean is significant.
b) We reject the hypothesis that the variables are dependent.
c) We accept the hypothesis that the variables are
independent.
d) We have sufficient evidence to reject the hypothesis that the
variables are independent.
e) The variables are independent.
8) A university anticipates that next year it will need to house 47% of its
undergraduate students. The student newspaper conducts a random sample of
50 freshmen, sophomores, and juniors who claim to be returning next year and
finds that 57% of the students indicate that they would need housing from the
university. Which of the following tests would be most appropriate for establishing
that the university should increase their estimate?
a) One sample t test of means
b) one sample proportion z test
c) Matched pair t test
d) one sample proportion t test
e) Chi-square test
MC 3rd Nine weeks test
1)E
2) E
3) D
4) B
5) C
6) A
7) A
8) A
9) D
10) D
11) B