Week4Hwk5020vb

Name:

ID:

Speed (Miles/Hour)

MPG (Miles/Gallon)

30

28

50

25

1

Two quantitative variables.

40

25

55

23

30

30

Variables

25

32

a

Which variable is the dependent variable?

Speed

60

21

b

Which variable is the independent variable?

MPG

25

35

50

26

55

25

c

Construct a scatter diagram with dependent variable on the vertical axis (Y)

and the independent variable on the horizontal axis (x)

Please label the chart and the axes.

d

What does the plot show about the relationship between the two variables?

Positive or negative? Weak or strong?

e

Using Excel function, compute the correlation of coeffient of the two variables.

f

What can you say about the linear relationship of the two variables based

on the correlation coefficient?

2

Bayes' Thereom

a

What is the probability that a randomly selected person in the US is 65 or older?

p(A)=

b

What is the probability that a randomly selected person in the US is under 65 years old?

p(NA)=

c

For a random selected person 65 or older, what is the probability that this person is uninsured?

p(U |A )=

d

For a random selected person under 65, what is the probability that this person is uninsured?

p( U|NA)=

This group includes under 18 and 18 to 64

e

Given that the person in the US is uninsured, what is the probability that the person is 65 or older?

p(A| U)=

p(A)*(p(u|A)

(hint: Use Bayes' Theorem)

---------------------------

p(A)*(p(u|A)+p(NA)*p(U|NA)

3

Contigency Table Problem

S&P 500's Annual Performance

First week

Higher

Lower

Total

Higher

37

5

42

Lower

11

11

22

Total

48

16

64

a

If a year is selected at random,

what is the probability that the S&P 500 finished lower for the year?

b

Given that the S&P fiished lower after the first five days of trading,

what is the probability that it finished lower for the year?

c

Are the two events "first week performance" and "annual performance"

independent?

Rename the completed worksheet and include your initials in the name. E.g. JDWeekX

End of this assignment.