NPTEL Data Science for Engineers Assignment 3 Answers 2023? In this article we will discuss about the answers for Week 3 assignment of Data science for Engineers. All these answers are make it as reference.  

Also Read: Nptel Data science for engineers Assignment 2 Answers

About NPTEL 

NPTEL ( National Programme on Technology Enhanced Learning). It is an online platform for providing free online courses to students and professionals in India. It is an initiative of the Ministry 

of Human Resource Development (MHRD), Government of India, in collaboration with seven Indian Institutes of Technology (IITs) and Indian Institute of Science (IISc). It provides high-quality and 

cost-effective education to students and professionals across the country. It offers courses through 

video lectures and interactive web-based courses. It also provides course material as PDFs, lecture slides, and practice exercises.  

Below you can find the answers for Data Science for Engineers Assignment 3 Answers 2023  

NPTEL Data Science for Engineers Assignment 3 Answers 2023 

Q1. Sumit wants to contact one of his friends, but he remembers only the first 9 of the 10 digits of 

       the contact number. He is sure that the last digit of the contact number is an odd number. 

      He selects an odd number randomly. If the random variable X denotes the last digit of the 

      contact number, then calculate Var(X). 

  a. 5

 b. 8 

 c. 33

 d. None of the above

 Answer: [ b ] 8

Q2. Suppose X∼Normal(µ,4). For n=20  iid samples of X , the observed sample mean is 5.2. 

       What conclusion would a z-test reach if the null hypothesis assumes µ=5

       (against an alternative hypothesis µ≠5 ) at a significance level of α=0.05 ? 

  Use F−1z(0.025)=−1.9599 

a. Accept Ho

b. Reject Ho

Answer: [ a ] Accept Ho

Q3. A box contains 8 items out of which 2 are defective. A sample of 5 items is to be 

      selected randomly (without replacement) from the box. If the random variable X

      represents the number of defective items in a selection of 5 items, then find E(X).

     (Enter the answer correct to 2 decimal places)

a.  1.25

b. 5

Answer: [ a ] 1.25

Q4. Suppose X∼Normal(μ,9). For n=100 iid samples of X, the observed sample mean is 11.8. 

      What conclusion would a z-test reach if the null hypothesis assumes μ=10.5

     (against an alternative hypothesis μ≠10.5)?  

a. Accept Ho at a Significance level of 0.10

b. Reject Ho at a Significance level of 0.10

c. Accept Ho at a Significance level of 0.05

d. Reject Ho at a Significance level of 0.05 

Answer: [ b , d ] Reject Ho at a Significance level of 0.10 ,Reject Ho at a Significance level of 0.05 

Q5. Let X and Y  be two independent random variables with Var(X)=9 and Var(Y)=3, 

       find Var(4X−2Y+6).

a. 100

b. 140

c. 156

d. None of the above

Answer: [ c ] 156

Q6. The correlation coefficient of two random variable X and Y is 14, their variance is given by 

       3 and 5. Compute Cov(X,Y).

a. -0.854

b. 0.561

c. -0.968

d. None of the above

Answer: [ d ] None of the above

Q7. When you reject the Null hypothesis ?

a. p value greater than α

b. p value less than α

c. p value equal than α

d. None of the above

Answer: [ b ] p value less than α 

Q8. A sample of N observations are independently drawn from a normal distribution. 

      The sample variance follows

a. Normal Distribution

b. Chi-square with N degrees of freedom

c. Chi-square with N−1 degrees of freedom

d. t distribution with N−1 degrees of freedom

Answer: [ c ] Chi-square with N−1 degrees of freedom.

Q9. A car manufacturer purchases car batteries from two different suppliers. Supplier provides

      55% of the batteries and supplier Y provides the rest. 5% of all batteries from supplier X

     are defective and 4% of all batteries from supplier Y are defective. You select a battery from 

     the bulk and you found it to be defective. What is the probability that it is from Supplier X ?

a. 0.0455

b. 0.455

c. 0.0275

d. 0.018

Answer: [ c ] 0.0275

Q10. Which one of the following is best measure of central tendency for categorical data?

a. Mean 

b. Median

c. Mode

d. None of the above

Answer: [ c ] Mode

Also Read: Nptel Data science for engineers Assignment 2 Answers  

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