How to practice Probability and Statistics

Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.

Questions 1–10 of 17. Imported answers require independent review unless marked reviewed.

Topic practice 17 questionsPage 1 of 2

Question 33

Open question
MTNAT1 markNeeds review
A box contains 20 thermometers, 3 of which are defective. One person randomly draws 2 thermometers from the box, one-by-one, without replacement. The probability in percent (rounded-off to two decimal places) that none of these TWO thermometers is defective, is _________________ %.

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 44

Open question
MTNAT2 marksNeeds review
Consider a distribution with the following probability density function

Given that the mean of the above probability distribution is 1, the variance (rounded off to two decimal places) is ________________.

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 35

Open question
MTNAT1 markNeeds review
A linear regression model was fitted to a set of

data. The total sum of squares and sum of squares of error are 120 and 12, respectively. The coefficient of determination (

) of the fit is _____ (rounded off to one decimal place).

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 11

Open question
MTMCQ1 markNeeds review
If

and

are independent normally distributed random variables with means

and

, and variances

and

, respectively, then the combination

has mean

and variance

such that
Your answerChoose one option.

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 13

Open question
MTMCQ1 markNeeds review
Consider the normal (Gaussian) distributions

,

,

shown in the figure.

and

are the standard deviation and mean of distribution

, respectively, and the means are positive. Which one of the following deductions is correct?
Diagram for Metallurgical Engineering question 13

Your answerChoose one option.

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 31

Open question
MTNAT1 markNeeds review
The probability of setting an easy exam paper by three setters are

,

, and

. If all three are setting one paper each, then the probability that at least one of the papers will be easy is __________ (round off to 2 decimal places).

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 34

Open question
MTNAT1 markNeeds review
A set of observations with normal distribution of error as ±1.96σ (where σ is standard deviation) is equivalent to the confidence interval of _______% (round off to the nearest integer).

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 64

Open question
MTNAT2 marksNeeds review
A set of 11 (x, y) data points is least-squares fitted to a quadratic polynomial. If the sum of squares of error is 2.4, the variance of error is ________ (round off to 1 decimal place).

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 7

Open question
GAMCQ2 marksNeeds review
A box contains 15 blue balls and 45 black balls. If 2 balls are selected randomly, without replacement, the probability of an outcome in which the first selected is a blue ball and the second selected is a black ball, is ______
Your answerChoose one option.

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer

Question 15

Open question
MTNAT1 markNeeds review
The grain size (X) of annealed specimens follows a symmetric distribution with a mean (μ) of 5 μm and a standard deviation (σ) of 0.5 μm. The percentage of specimens with grain size in the range 5 to 6 μm is expected to be: __________ (round off to nearest integer).
Given: For the symmetric distribution: Probability P(X ≤ μ + 2σ) = 0.98

Log in to check the answer

You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer