Estatística e Probabilidade Practice Questions
ENEM (Brazil) · ENEM Matemática · 143 free MCQs with instant results and detailed explanations.
143
Total
41
Easy
76
Medium
26
Hard
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Sample Questions from Estatística e Probabilidade
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
A survey shows that 40% of students prefer online classes over traditional classes. If 100 students were surveyed, how many prefer online classes?
A.
40
B.
60
C.
30
D.
50
Show Answer & Explanation
Correct Answer: A
To find how many students prefer online classes, calculate 40% of 100, which is (40/100) * 100 = 40. Therefore, 40 students prefer online classes.
Q2
Easy
A student scores the following marks in five subjects: 70, 85, 90, 75, and 80. What is the average score of the student?
A.
80
B.
85
C.
75
D.
90
Show Answer & Explanation
Correct Answer: A
The average is calculated by summing all scores (70 + 85 + 90 + 75 + 80 = 400) and dividing by the number of subjects (5). So, 400/5 = 80.
Q3
Easy
In a class of 30 students, 18 are girls. What is the probability that a student chosen at random is a girl?
A.
0.6
B.
0.5
C.
0.4
D.
0.3
Show Answer & Explanation
Correct Answer: A
The probability of selecting a girl is calculated as the number of girls divided by the total number of students. Thus, P(girl) = 18/30 = 0.6.
Q4
Medium
In a certain city, the average monthly temperature in degrees Celsius is 25 with a standard deviation of 5. If the temperatures are normally distributed, what percentage of the months have temperatures between 20 and 30 degrees?
A.
68%
B.
95%
C.
50%
D.
34%
Show Answer & Explanation
Correct Answer: A
According to the empirical rule, about 68% of data in a normal distribution lies within one standard deviation of the mean. Here, 20 to 30 degrees covers one standard deviation below and above the mean.
Q5
Medium
A survey of 200 students found that 60% prefer online classes over in-person classes. If a random sample of 10 students is chosen, what is the probability that exactly 6 students prefer online classes?
A.
0.1116
B.
0.2001
C.
0.2515
D.
0.3434
Show Answer & Explanation
Correct Answer: C
Using the binomial probability formula P(X=k) = (nCk)(p^k)(1-p)^(n-k), where n=10, k=6, and p=0.6, we calculate the probability for exactly 6 students preferring online classes.
Q6
Medium
A die is rolled twice. What is the probability that the sum of the two rolls is greater than 8?
A.
1/12
B.
5/12
C.
7/12
D.
1/2
Show Answer & Explanation
Correct Answer: C
To find the probability of the sum being greater than 8, we first determine the total outcomes (36) and the favorable outcomes (21). Therefore, the probability is 21/36 which simplifies to 7/12.
Q7
Medium
If the median of a dataset is 25 and the data consists of 7 numbers, which of the following could be the mode of the dataset?
A.
20
B.
25
C.
30
D.
10
Show Answer & Explanation
Correct Answer: B
The median being 25 indicates that 25 is the middle value when arranged in order. The mode can be any value that appears most frequently, including 25 itself, making it a plausible mode.
Q8
Hard
In a certain city, the average monthly temperature is 25°C with a standard deviation of 5°C. If the temperatures in a month follow a normal distribution, what is the probability that the temperature will be between 20°C and 30°C?
A.
0.68
B.
0.95
C.
0.50
D.
0.32
Show Answer & Explanation
Correct Answer: A
According to the empirical rule for normal distributions, approximately 68% of values lie within one standard deviation of the mean. Since 20°C and 30°C are one standard deviation away from the mean of 25°C, the probability is about 0.68.
Q9
Hard
In a population of students, the average age is 20 years with a standard deviation of 2 years. If we assume the ages are normally distributed, what percentage of students are likely to be older than 22 years?
A.
16%
B.
32%
C.
50%
D.
84%
Show Answer & Explanation
Correct Answer: A
In a normal distribution, approximately 16% of the values lie above one standard deviation from the mean. Since 22 is one standard deviation above the mean of 20, about 16% of students are expected to be older than 22.
Q10
Hard
A bag contains 5 red balls, 3 blue balls, and 2 green balls. If three balls are drawn at random without replacement, what is the probability that all three balls are of different colors?
A.
1/10
B.
1/15
C.
1/5
D.
2/15
Show Answer & Explanation
Correct Answer: D
To find this probability, calculate the total ways to draw 3 balls of different colors and divide it by the total ways to draw any 3 balls from 10 (which is 120). The successful outcomes are calculated using combinations. Hence, the probability is 2/15.
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Estatística e Probabilidade — ENEM (Brazil) ENEM Matemática Practice Questions Online
This page contains 143 practice MCQs for the chapter Estatística e Probabilidade in ENEM (Brazil) ENEM Matemática. The questions are organized by difficulty — 41 easy, 76 medium, 26 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.