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STAT 442 ASSIG ME T-1
Second Semester 1430-1431 H
Question -1 :
From the book ( Using R for introductory statistics) , Solve the following exercises:
a) Page: 14-15-16 Problems : 4[3,4], 5[3,4], 7, 8 , 9, 10, 12, 13 b) Page: 22 Problems: 16, 17
c) Page: 29 Problems: 20,21,23
Question -2 :
The marks of six student in two exams were : first second
A 3 6
B absent absent
C 8 16
D 10 20
E absent absent
F 6 12
1) Inter the above table to R ( consider the absent student’s mark as missing)
2) Chick for all six student that the marks of second exam is multiple the marks of first exam
3) Change the mark of student B to (7) for the first exam and (13) for the second exam And the mark of student E to (6) for the first exam and (10) for the second exam 4) Is still second exam multiple of first exam ??
5) Find the second exam’s mark of students who get mark (8) or more in the first exam
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Question -3:
Let x= 6 , 4 , -2 , 7 , 6 , -3 ; as temperatures in the winter season of seven days 1) find (without using of built-in function in R)
a) Square root of x and the absolute value of x.
b) mode.
c) median.
d) Coefficient of variation.
e) Correlation between x and y, if y= 12 , 3 , 9 , 14 , 10 , 8 f) Inter (2) after the temperatures of third day .
2) Check your answer by built-in function in R .
Question -4:
The number of students in four courses according to their department are : Course-a Course-b Course-c Course-d
Stat department 25 21 20 22
Math department 45 27 23 24
Bio department 17 32 26 29
Chem department 20 18 35 27
1) Create the above table with the row’s and column’s names (using paste on names) , name it “Student numbers”.
2) Find the student number of Chem department in the Course-d . 3) Find the mean of students of Course-b and Course-c .
4) Find the course which contain the minimum number of Stat department.
5) Remove three student from each department in Course-a
6) Change the data as there are two more student of Stat department register in Course-d
7) Inter a new column “Total number” which contain the sum of students in each course, such that the student number is less than 25 .
Question -5:
The data set (juul) in the (ISwR) package contains a reference sample of the distribution of insulin-like growth factor (IGF-I) (ومنلا لدعم ىلع نيلوسنلااب ةھيبش ةدام ريثأت)
1) Write the logical expression to extract girls between 7 and 14 years of age , Using two methods ( use attach( ) , don’t use attach( ) )
2) Find the number of girls between 7 and 14 years of age (only girls without missing )
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Question -6:
Create the given matrix, then change the diagonal’s element of the matrix as follows:
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−
−
−
−
6 . 4 1 5 . 0 4 8
5 6 8 3 . 7 3
2 3 4 . 2 2 3
5 . 4 10 4 5 2
4 . 9 1 7 . 0 3 5 . 1
a) Change the negative decimal number (fractional number) to 1 b) Change the positive decimal number (fractional number) to 2 c) Change the negative integer number (without fraction) to 3 d) Change the positive integer number (without fraction) to 4
write a command as general command
(i.e you can use the same command for any other matrix with any diminution )
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Best Wishes…
Dr.Lamya Baharith I.Mariam Khan
