106 Lectures 106student.pdf
Text Book:
Elementary Biostatistics with Applications from Saudi Arabia. by NancyA. E. Hasabelnaby.
STAT 106
Biostatistics (1+1) credithours.
Beneficiaries: College of Medicine.
Descriptive statistics  Measure of location and dispersion  Elementary probability  Random variable and probability distribution  Central limit theorem and application.
106 احص(1+1)
إحصاء حيوي
إحصاء وصفي : بيانات كمية ووصفية وتمثيلها بيانياً ، مقاييس النزعة المركزية ، مقاييس التشتت ، بعض القواعد والاحتمالات البسيطة ، المتغير العشوائي ، توزيع ذي الحدين وتوزيع بواسون ، التوزيع الطبيعي وتطبيقه ، إيجاد فترة ثقة لمتوسط ونسبة .
Exam_106.doc
Homework 1
For a sample of children with frequent toothache, we measure the number of times a child has been to a doctor in the last year as follows:
Number of times 
1 
2 
3 
4 
5 
Number of child 
15 
10 
8 
4 
3 
A) What is the name of the variable?
B) What is the type of the variable?
C) What is the sample size?
D) How many children have been to a doctor 3 times?
E) How many children have been to a doctor 4 times or more?
F) How many children have been to a doctor from 2 to 4 times?
G) What is largest value of the variable?
H) What is the percentage of the children has been to a doctor less than 3 times?
I) What is the number of times a child has been to a doctor with highest percentage?
Homework 2
we measure the excess in weight (in kilogram) for a sample of pregnant women:
Classes 
True classes 
midpoint 
Frequency 
Relative frequency 
Cumulative relative frequency 
4  6
7  9
10  12
13  15
16  18 


12
15
11
8
4 








Complete the table to answer the following questions:
1) 4^{th} true class is:
2) 3^{rd} midpoint is:
3) 2^{nd} relative frequency is:
4) 4^{th} cumulative relative frequency is:
5) How many women had excess in weight of 10 or more?
6) What percent of women had excess in weight from 4 to less than 12?
7) Which class of weight had the highest percentage of women?
Homework 3
For a certain operation, x = the time to complete the operation (in hours) has a normal distribution with mean 5 and standard deviation of 0.5. For randomly chosen operation, find the probability that the time to complete is:
[1] more than 6 hours:
(a) 0.9772 (b) 0.0228 (c) 0.1587 (d) 0.8413
[2] less than 4.5 hours:
(a) 0.8413 (b) 0.0228 (c) 0.1587 (d) 0.8185
[3] between 4.0 and 5.5 hours:
(a) 0.0228 (b) 0.8413 (c) 0.1587 (d) 0.8185
[4] equal to 3.2 hours:
(a) 0.0007 (b) 0.9993 (c) 0 (d) 1
Homework 4
In a certain hospital, the number of patients admitted per week has the Poisson distribution with mean 7.
(a) Find the probability that on a particular day,
(i) no patient is admitted by the hospital,
(ii) at least two patients are admitted by the hospital,
(b) How many patients is the hospital expected to admit in
(i) two weeks,
(ii) one month?
Homework 5
For a child, the variable X= the number of times he eat in a certain day,َWhere 0≤X≤4. The following probabilities are given:
P(X=3) = 0.15, P(X=2) =0.2, P (X≥3) = 0.35, P (0<X≤2) =0.55.
Then,
[1] P(X= 4) = (a) 0.1 (b) 0.3 (c) 0.15 (d) 0.2 (e) 0
[2] P(X= 0) = (a) 0.25 (b) 0.3 (c) 0.1 (d) 0.5 (e) 0
[3] The expected number of candy he ate in a day:
(a) 1 (b) 4 (c) 0 (d) 0.5 (e) 2