Question 1
The probability of a man hitting a target is 1/4. If he fires 5 times, then find the probability that he will hit the target at least twice.
The IIT Madras BS Statistics for Data Science I (Stats 1) End Term paper sat on 28 Apr 2024, in the January 2024 term: 19 questions for 50 marks in 180 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
The probability of a man hitting a target is 1/4. If he fires 5 times, then find the probability that he will hit the target at least twice.
Correct answer
Correct answers
Choose the correct option(s) from the following.
Correct answers
Which of the following option(s) is/are correct for a variable with interval scale of measurement?
Difference between the values of a variable can be evaluated.
Order of the data is meaningful.
Multiplication and division of values of a variable is possible.
It has an absolute zero.
Correct answers
Difference between the values of a variable can be evaluated.
Order of the data is meaningful.
Which of the following statement(s) is(are) correct?
We must preserve the order of an ordinal data in a bar chart.
Mode is not defined for an ordinal data.
Mean can be calculated for a categorical data.
Covariance can be computed only for two numerical variables.
Correct answers
We must preserve the order of an ordinal data in a bar chart.
Covariance can be computed only for two numerical variables.
If the mean of the observations 2a, 10, 3a, 50 and 40 is 30, then find the median of the dataset.
Correct answer: 30
Correct answer: 3.66 (accepted within ±0.04)
In the first semester of B.S. degree, a student is expected to take 4 subjects. The grades for each subject can be S(10points),A(9points),B(8points),C(7points),D(6points),E(5points) and F(Fail). As per the rules, an enrolled student should obtain a minimum grade E in each subject to get promoted to the next semester. What is the total number of possible ways in which a student can get promoted?
Correct answer: 1296
The mean and sample standard deviation of the dataset consisting of 8 observations is 15 and 11 respectively. Later it is noted that one observation 13 is wrongly noted as 10. What is the mean of the original dataset? Enter the answer correct to two decimal places.
Correct answer: 15.38 (accepted within ±0.3)
In a company, 120 employees are divided into three departments: Marketing, Finance and IT. The number of employees in each department is as follows: 36 in Marketing, 40 in Finance and 44 in IT. An employee, out of 120, is randomly selected for a presentation. Let X denote the number of employees in the department to which that employee belongs. Based on the given information, answer the given subquestions.
Identify the correct distribution of X.
Correct answer
In a company, 120 employees are divided into three departments: Marketing, Finance and IT. The number of employees in each department is as follows: 36 in Marketing, 40 in Finance and 44 in IT. An employee, out of 120, is randomly selected for a presentation. Let X denote the number of employees in the department to which that employee belongs. Based on the given information, answer the given subquestions.
Find the expected value of X. Enter the answer correct to two decimal places.
Correct answer: 40.27 (accepted within ±0.03)
A manufacturing company produces steel rods with lengths between 20 cm and 40 cm. Assume length of steel rods follows a uniform distribution.
Based on the given information, answer the given subquestions.
Correct answer: 30
A manufacturing company produces steel rods with lengths between 20 cm and 40 cm. Assume length of steel rods follows a uniform distribution.
Based on the given information, answer the given subquestions.
What is the probability that a randomly selected steel rod will have a length of more than 25 cm?
Correct answer
Suppose the time taken by a delivery service to deliver a package (in hours) follows an exponential distribution with a mean delivery time of 10 hours. If someone places an order just before you, then based on the given information, answer the given subquestions.
What is the probability that you will have to wait more than 15 hours for your package to be delivered?
Correct answer
Suppose the time taken by a delivery service to deliver a package (in hours) follows an exponential distribution with a mean delivery time of 10 hours. If someone places an order just before you, then based on the given information, answer the given subquestions.
What is the probability that you will have to wait between 15 hours and 30 hours?
Correct answer
Based on the above data, answer the given subquestions.
Find the value of λ for which 3P(X = 3) = 2P(X = 2) + 4P(X = 1).
2
4
1
−2
Correct answer
4
Based on the above data, answer the given subquestions.
Correct answer: 0.38 (accepted within ±0.03)
Based on the above data, answer the given subquestions.
What is the probability that a patient has the disease and the test is positive?
Correct answer
Based on the above data, answer the given subquestions.
Find the probability that a patient has the disease given that the test is positive.
Enter the answer correct to two decimal places.
Correct answer: 0.42 (accepted within ±0.03)