Mazen took 5 penalty kicks and scored 3 goals. If he takes 20 kicks, the expected number of goals is :
6
9
12
15
The probability that a football team wins is 0.75. Out of 24 matches, how many are expected to be won :
18
20
Biased selection is :
Randomly selecting members of the population without bias
Intentionally selecting specific individuals that suit the research objectives
The method of complete enumeration of all population members
Giving every individual an equal chance of being selected in the sample
The statistical population is all the individuals the researcher is interested in studying. The population for a researcher studying students of a school is:
Top-performing students
All students
School teachers
A sample of students
Data collection methods include:
Complete enumeration and sampling together as needed
Complete enumeration only without using sampling
Personal interviews only without other methods
Sampling only without using complete enumeration
The sampling method is appropriate in all of the following cases EXCEPT:
Inspecting desert sand
Taking a patient's blood test
Knowing the population count
Inspecting a factory's production
A factory produces 120 washing machines daily. The probability of a machine being defective is 0.05. The expected number of non-defective machines is :
114
120
130
The complete enumeration method is appropriate for which of the following:
Knowing the number of students who received the full mark
Researching the percentage of minerals in large mining areas
Researching the components of desert sand spread over vast areas
Examining the sweetness ratio of a well's water in the region
The probability of a good rice harvest is 3/5. If X feddans are cultivated and 30 feddans are expected to produce a good harvest, then X equals :
36
42
50
A factory has 320 workers and engineers. A sample of 16 individuals was taken, with 5 engineers. The expected number of engineers in the factory is :
100
160
220
Two factories produce 210 TVs together: Factory 1 produces 110 (10 defective), Factory 2 produces 100 (18 defective). The probability of selecting a device from Factory 2 that is defective is:
18/210
12/100
18/110
30/210
A board: outer square 25×25 cm and inner square 15×15 cm. The probability of hitting the outer (uncolored) region is:
9/25
16/25
1/5
4/5
An insurance company: 3,500 EGP compensation, probability of injury 0.006, 9,000 subscribers. The expected total compensation is :
31,500
54
189,000
162,000
The probability of scoring a goal from a handball penalty is 60%. The expected number of goals from 30 throws is:
30
In a sample of 60 people: 45 speak English, 30 speak French, and 25 speak both. The probability of NOT speaking either language is:
1/6
5/6
5/12
7/12
Sales from 5 outlets: each sells 80 shoes. Sales of Type 1: 45, 48, 24, 19, 35. The probability of selling Type 1 is:
0.57
0.43
0.71
0.29
A school has 400 male students and 500 female students, and a stratified sample of 45 individuals was taken. The number of male students in the sample is :
25
One type of primary data collection source is :
Employee databases that are already stored
Personal interviews
The Internet
Bulletins from the Central Statistical Agency
Which of the following is a secondary data collection source
Employee database
Observation and measurement
Questionnaires
A sample is:
A secondary data source that was previously collected
A small part of a large population that resembles and represents it
The entire population with all its members
A method to enumerate the population and study all its members
A sample of 30 students from 750 students: Football 15, Swimming 8, Handball 4, Volleyball 3. The probability that a selected student prefers Swimming is :
8/15
8/30
4/30
A factory has 180 workers, 120 technicians, and 100 engineers. A stratified sample of 40 people was taken. The number of engineers in the sample equals :
10
17
A large circle with radius 15 cm and a small colored circle with radius 9 cm. The probability of hitting the colored part is:
144/225
72/225
A school has 350 students, and a simple random sample of 10% was taken. The number of students in the sample is:
35
40
A class of 60 students: 35 watched educational programs, 25 entertainment, 10 watched both. The probability that a student watched educational programs only is:
1/4
A factory: 500 of Model 1, 700 of Model 2, and 300 of Model 3. A stratified sample of 7% of production. The number of Model 1 items in the sample is:
21
49
105
A stratified random sample is taken from a population of 5000 in 4 strata. The first stratum has 1500 individuals, with 225 in the sample. The total sample size is :
500
600
700
750
A media team consists of 18 members: 4 teachers, 8 male students, and 6 female students. If one member is selected at random, the probability that the selected member is a student (male) or a teacher is :
2/9
1/3
4/9
2/3
A company has 300 workers. A simple random sample of 10% of the workers was taken. The sample size equals :
In a class of 36 students, 12 passed the Arabic Language subject. If a student is selected at random, the probability that the selected student has failed is :
3/4
A hospital has 40 doctors and 200 nurses. A stratified sample of 36 individuals was taken, each stratum represented proportionally. The number of nurses in the sample equals:
24
A medical team consists of 60 doctors and 12 nurses. The probability of selecting a nurse is :
12/60
A school has 1200 students. A sample of 90 students was taken, of whom 54 are girls. The expected number of girls in the school is :
480
660
720
840
In a sample of 80 students: 60 prefer Mathematics, 45 prefer Social Studies, and 35 prefer both. The probability of preferring at least one of the two subjects is :
7/8
7/16
1/8
9/16
A sample of 60 visitors: Arab male 24, Foreign male 8, Arab female 16, Foreign female 12. The probability that the selected person is male or foreign is :
7/15
11/15
A study on wearing prescription glasses with a sample of 50 students: 30 boys and 20 girls; 10 boys and 5 girls wear glasses. What is the probability that the selected person is a boy who does NOT wear glasses:
15/40
9/40
2/5
A company exports: 96,280 tons of onions, 82,220 tons of potatoes, and 11,500 tons of grapes. If exports rise to 380,000 tons with the same ratios, the expected export of grapes (in tons) is:
12,000
22,840
23,000
46,000
A factory produces 800 light bulbs daily. The probability that a bulb is defective is 0.03. The expected number of non-defective bulbs is :
124
560
776
In a sample of 75 people: 45 speak English, 25 speak French, 10 speak both. The probability that a randomly selected person speaks at least one language is :
3/5
7/10
In a sample of 80 students: 60 prefer Mathematics, 45 prefer Social Studies, and 35 prefer both. Total school: 2000. The expected number of students who prefer Social Studies only is:
125
250
375