QUESTION 1   a) The table below gives the frequency distribution of marks obtained by a group of students in a class test. Marks 3 4 5 6 7 8 Frequency 5 x-1 x 9 4 1   i) Find the value of x  if the mean for the distribution is 5.                  ii) What is the modal mark. iii) Find the mean absolute deviation. iv) Find the sample variance and the sample standard deviation   b) By using the phrases “correct decision” or “wrong decision”, complete the decision table for hypothesis testing below. Where the decision is wrong, state the type of error committed. DECISION    H0 is false H0 is true Reject H0     Fail to Reject H0       (c)  In the test of a certain hypothesis the p-value corresponding to the test statistics is 0.0316. Can the null hypothesis be rejected at the; i) 01 level of significance? ii) 05 level of significance? 10 level of significance? Justify your answers.                                                                           QUESTION 2 The following data represents the amount in kg of fertilizer applied to equal size of plots and the yields in kg of maize. PLOT AMOUNT OF FERTILIZER(X) YIELDS(Y) A 2 7 B 1 3 C 3 8 D 4 10

Glencoe Algebra 1, Student Edition, 9780079039897, 0079039898, 2018
18th Edition
ISBN:9780079039897
Author:Carter
Publisher:Carter
Chapter10: Statistics
Section10.3: Measures Of Spread
Problem 26PFA
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QUESTION 1

 

a) The table below gives the frequency distribution of marks obtained by a group of students in a class test.

Marks

3

4

5

6

7

8

Frequency

5

x-1

x

9

4

1

 

i) Find the value of x  if the mean for the distribution is 5.                 

ii) What is the modal mark.

iii) Find the mean absolute deviation.

iv) Find the sample variance and the sample standard deviation

 

b) By using the phrases “correct decision” or “wrong decision”, complete the decision table for hypothesis testing below. Where the decision is wrong, state the type of error committed.

DECISION

   H0 is false

H0 is true

Reject H0

 

 

Fail to Reject H0

 

 

 

(c)  In the test of a certain hypothesis the p-value corresponding to the test statistics is 0.0316. Can the null hypothesis be rejected at the;

i) 01 level of significance?

ii) 05 level of significance?

  • 10 level of significance?

Justify your answers.

 

                                                                        QUESTION 2

The following data represents the amount in kg of fertilizer applied to equal size of plots and the yields in kg of maize.

PLOT

AMOUNT OF FERTILIZER(X)

YIELDS(Y)

A

2

7

B

1

3

C

3

8

D

4

10

 

i) Calculate and interpret the correlation coefficient for X and Y

ii) Calculate and interpret the least square regression of Y on X

 

c) Find the value of a, b, …, f in the one-way ANOVA table below.

Source

SS

df

MS

F

Treatment

361.5

b

60.25

f

Error

a

21

d

 

Total

821.7

c

e

 

 

QUESTION 3

Suppose that the random variable, X, is a number on the biased die and the p.d.f. of  X is as shown below;

X

1

2

3

4

5

6

P(X=x)

1/6

1/6

1/5

k

1/5

1/6

Find;

  • the value of
  • E(X)
  • E(X2)
  • Var(X)
  • P(1 X <5)

 

b) If events A and B are such that they are independent, and P(A) = 0.3 with P(B) = 0.5;

i) Find P(A n B) and P(AUB)

ii) Are A and B mutually exclusive?                                       

iii) In how many ways can the letters of the word STATISTICS be arranged? 

iv) State three (3) characteristic properties of a Normal Distribution curve.

 

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