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Independent random samples from normal distributions with equal variance of the amount of insider
trading during mergers by employees of investment banking firms (1) and brokerage houses (2) gave the
results listed in the accompanying table.
Investment Banking Firm 10 5 5 5 8 8 8
Brokerage House 6 0 5 2 2 3 3
(a) Find the 95% confidence interval estimate for the difference between means ยต1 โ ยต2..
(b) Would you conclude that employees of Investment banking firms cause more insider trading than
their counterparts in Brokerage House?
the demand function ๐(๐) and cost functions ๐ถ(๐) of a commodity are given by the equations:
๐=12000โ60๐
๐ถ(๐)=10000+4๐,
where ๐ and ๐ are the price and quantity, respectively.ย
The total revenue function ๐๐ in terms of ๐ is:
a.
๐๐ =12 000โ60๐.
b.
๐๐ =๐(12 000โ60๐2).
c.
๐๐ =12 000๐โ60๐2.
d.
๐๐ =12 000+60๐2.
Conduct Hypothesis Testing Using Small-Sample Tests. Step- By- Step.
An experimental study was conducted by a researcher to determine if new time slot has an effect on the performance of students in mathematics. Ten randomly selected students participated in the study. Toward the end of the investigation, a standardized assessment was conducted. The sample mean was X=75 and the standard deviation s=20. In the standardization of the test, the mean was 65 and the standard deviation was 10. Based on the evidence at hand, is the new time slot effective? Use ฮฑ=0.05.
A survey of 100 similar-sized hospitals revealed a mean daily census in
the pediatrics service of 27
with a standard deviation of 6.5. Do these data provide sufficient evidence to
indicate that the
1. population mean is greater than 25? Let alpha = 0.5
We wish to know if we can conclude that the mean daily caloric intake in
the adult rural population of
a developing country is less than 2000. A sample of 500 had a mean of 1985
and a standard deviation
of 210. Let alpha = 0.5
A sample of 25 freshman nursing students made a mean score of 77 on a
test designed to measure
attitude toward the dying patient. The sample standard deviation was 10. Do
these data provide
sufficient evidence to indicate, at the .05 level of significance, that the
population mean is less than
80? What assumptions are necessary?
Nine laboratory animals were infected with a certain bacterium and then
immunosuppressed. The
mean number of organisms later recovered from tissue specimens was 6.5
(coded data) with a
standard deviation of .6. Can one conclude from these data that the
population mean is greater than 6?
Let alpha = 0.5What assumptions are necessary?
In a sample of 49 adolescents who served as the subjects in an
immunologic study, one variable of
interest was the diameter of skin test reaction to an antigen. The sample mean
and standard deviation
were 21 and 11mm erythema, respectively. Can it be concluded from these
data that the population
mean is less than 30? Let alpha = 0.5
The purpose of a study by Lugli_e et al. (A-5) was to investigate the oral
status of a group of patients
diagnosed with thalassemia major (TM). One of the outcome measures was
the decayed, missing, and
filled teeth index (DMFT). In a sample of 18 patients the mean DMFT index
value was 10.3 with a
standard deviation of 7.3. Is this sufficient evidence to allow us to conclude
that the mean DMFT
index is greater than 9.0 in a population of similar subjects? Let alpha = 0.1
The table below gives the scores of Students on a English Examinations
under KCSE
Student
1
2
3
4
5
6
7
8
9
Oral test
B-
B+
B
A-
A
B
C+
B
C-
Composition
10
21
22
19
17
14
13
16
12
Literature
34
76
74
60
68
44
45
53
43
(Composition test is out of 30 and literature test is out of 100 marks)
(a) Calculate the value of the most appropriate measure of correlation between the results
in the oral and composition tests, justifying your choice of measure. Interpret the value you
obtain.
(b) Calculate the value of the most appropriate measure of correlation between the results in
the composition and literature tests, justifying your choice of measure. Interpret the value
you obtain.
