Statistics and Probability Answers

The following values show the IQ and the Entrance Exam scores of incoming freshmen in a certain university.

Student

IQ (x)

Entrance Exam scores (y)

1

120

98

2

85

78

3

90

88

4

110

95

5

115

97

6

124

99

7

89

88

8

98

92

9

99

93

10

100

91

Calculate the following:

a. Compute the value of correlation coefficient ®.

b. What is the least-squares equation?

c. If student 11 has an IQ = 130, what is his/her estimated entrance exam score?

The probability density function of two random variables is f(x1,x2)=e^-(x1+x2) x1>0 , x2>0 given that y=x1/(x1+x2)what is the probability density function of variabley

question2:

Force (N) 0 20 40 60 80

Length (mm) 22 110 215 330 410

Use the table of measurements of length and

force that you have been supplied with to

complete the following activities:

(a) Draw a scatter graph for your given data.

Describe what the scatter graph is indicating.

(b) Use the scatter graph to estimate the

length for a force of 57N

(c) Calculate the line of regression of

extension on force (Y on X)

(d) Calculate the regression coefficient

(e) Explain what the regression coefficient

indicates?

(f) Use the equation for the line of regression

to predict the length for a force of 57N

(g) Compare the calculated value with the

value that you have determined from the

scatter graph.

(4.6 4.5 4.7 4.6 4.5 4.6 4.3 4.6 4.8 4.2

4.6 4.5 4.7 4.5 4.5 4.6 4.6 4.6 4.8 4.6)

1. Use the ungrouped data that you have been

supplied with to complete the following:

(a) Arrange the data into equal classes

(b) Determine the frequency distribution

(c) Draw the frequency histogram

(d) Create a cumulative frequency table for

the data

(e) Draw the cumulative frequency graph

(f) Use your cumulative frequency graph to

determine if the data is normally distributed

or not?

(g) Calculate: i) the mean and standard

deviation; li) the upper and lower quartile

values; and ili) the interquartile range for the

given data.