A manager of a sports club keeps information concerning the main sport in which members participate and their ages. To test whether there is a relationship between the age of a member and his or her choice of sport, 643 members of the sports club are randomly selected. Conduct a test for independence.
Sport
18 - 25
26 - 30
31 - 40
41 and over
racquetball
42
58
30
46
tennis
58
76
38
65
swimming
72
60
65
33
6
25.21
0.0003
Decision: Reject null
A major food manufacturer is concerned that the sales for its skinny French fries have been decreasing. As a part of a feasibility study, the company conducts research into the types of fries sold across the country to determine if the type of fries sold is independent of the area of the country. The results of the study are below. Conduct a test for independence.
Type of Fries
Northeast
South
Central
West
skinny fries
70
50
20
25
curly fries
100
60
15
30
steak fries
20
40
10
10
According to Dan Lenard, an independent insurance agent in the Buffalo, N.Y. area, the following is a breakdown of the amount of life insurance purchased by males in the following age groups. He is interested in whether the age of the male and the amount of life insurance purchased are independent events. Conduct a test for independence.
Age of Males
None
<$200,000
$200,000 - $400,000
$401,001 - $1,000,000
$1,000,000 +
20 - 29
40
15
40
0
5
30 - 39
35
5
20
20
10
40 - 49
20
0
30
0
30
50 +
40
30
15
15
10
12
125.74
0
Decision: Reject null
Suppose that 600 thirty–year–olds were surveyed to determine whether or not there is a relationship between the level of education an individual has and salary. Conduct a test for independence.
Annual Salary
Not a high school graduate
High school graduate
College graduate
Masters or doctorate
<$30,000
15
25
10
5
$30,000 - $40,000
20
40
70
30
$40,000 - $50,000
10
20
40
55
$50,000 - $60,000
5
10
20
60
$60,000 +
0
5
10
150
A Psychologist is interested in testing whether there is a difference in the distribution of personality types for business majors and social science majors. The results of the study are shown below. Conduct a Test of Homogeneity. Test at a 5% level of significance.
Open
Conscientious
Extrovert
Agreeable
Neurotic
Business
41
52
46
61
58
Social Science
72
75
63
80
65
4
Chi-Square with df = 4
3.01
p-value = 0.5568
ii. Do not reject the null hypothesis.
iv. There is insufficient evidence to conclude that the distribution of personality types is different for business and social science majors.
Do men and women select different breakfasts? The breakfast ordered by randomly selected men and women at a popular breakfast place is shown below. Conduct a test of homogeneity. Test at a 5% level of significance
French Toast
Pancakes
Waffles
Omelettes
Men
47
35
28
53
Women
65
59
55
60
3
4.01
p-value = 0.2601
ii. Do not reject the null hypothesis.
iv. There is insufficient evidence to conclude that the distribution of breakfast ordered is different for men and women.
Is there a difference between the distribution of community college statistics students and the distribution of university statistics students in what technology they use on their homework? Of the randomly selected community college students 43 used a computer, 102 used a calculator with built in statistics functions, and 65 used a table from the textbook. Of the randomly selected university students 28 used a computer, 33 used a calculator with built in statistics functions, and 40 used a table from the textbook. Conduct an appropriate hypothesis test using a 0.05 level of significance.
2
7.05
p-value = 0.0294
ii. Reject the null hypothesis.
iv. There is sufficient evidence to conclude that the distribution of technology use for statistics homework is not the same for statistics students at community colleges and at universities.
Questions & Answers
find the 15th term of the geometric sequince whose first is 18 and last term of 387
In this morden time nanotechnology used in many field .
1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc
2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc
3- Atomobile -MEMS, Coating on car etc.
and may other field for details you can check at Google
Azam
anybody can imagine what will be happen after 100 years from now in nano tech world
Prasenjit
after 100 year this will be not nanotechnology maybe this technology name will be change .
maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
Azam
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
Prasenjit
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
Damian
silver nanoparticles could handle the job?
Damian
not now but maybe in future only AgNP maybe any other nanomaterials
Azam
Hello
Uday
I'm interested in Nanotube
Uday
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
Prasenjit
can nanotechnology change the direction of the face of the world
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.