Category: Data Science Objective Questions

Data Science Interview Questions and Answers for experienced focuses on “Reading from Web and API”.

1. Which of the following package is used to connect MySQL RDBMS with R?
a) RMySQL vignette
b) MySQL vignette
c) RSQL vignette
d) None of the mentioned

Answer: a
Explanation: This package contains meta information and index.

2. Point out the correct statement.
a) HDF5 is a hierarchical format
b) HDF5 does not support range of different data types
c) HDF5 is used for storing small datasets
d) None of the mentioned

Answer: a
Explanation: HDF5 is used for storing large datasets.

3. Which of the following is used to extract data from HTML code of websites?
a) Webscraping
b) Webdredging
c) Webcleaning
d) All of the mentioned

Answer: a
Explanation: Webscraping is a great way to get data.

4. Which of the following function is used to read data off the webpages?
a) read.web
b) read.Lines
c) read.Line
d) all of the mentioned

Answer: b
Explanation: read.Lines function will extract the web page data.

5. Point out the wrong statement.
a) hdf5 can be used to reading/writing from disc in Python
b) rhdf5 is an interface for hdf5 format
c) maximum size of an HDF5 dataset is fixed when it is created
d) all of the mentioned

Answer: b
Explanation: hdf5 can be used to reading/writing from disc in R.

6. Which of the following package is used for reading HTML and XML data?
a) httr
b) http
c) httx
d) all of the mentioned

Answer: a
Explanation: httr contains tools for Working with URLs and HTTP.

7. httr package does not work well with facebook and twitter API.
a) True
b) False

Answer: b
Explanation: Most modern APIs use something like oauth.

8. Which of the following request can be issued from httr package?
a) GET
b) PUT
c) DELETE
d) All of the mentioned

Answer: d
Explanation: Authentication is necessary for issuing a request.

9. Which of the following package loads data from SPSS?
a) read.spss(SPSS)
b) read.oct(SPSS)
c) read.xpot(SPSS)
d) all of the mentioned

Answer: a
Explanation: SPSS is a comprehensive and flexible statistical analysis and data management solution.

10. Which of the following package is used for reading GIS data?
a) rdgal
b) rgeos
c) raster
d) all of the mentioned

Answer: d
Explanation: A geographic information system is a system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data.

Basic Data Science questions on “Statistical Inference Concepts”.

1. Which of the following testing is concerned with making decisions using data?
a) Probability
b) Hypothesis
c) Causal
d) None of the mentioned

Answer: b
Explanation: The null hypothesis is assumed true and statistical evidence is required to reject it in favor of a research or alternative hypothesis.

2. Point out the correct statement.
a) Power of a one sided test is lower than the power of the associated two sided test
b) Power of a two sided test is greater than the power of the associated one sided test
c) Hypothesis testing is less commonly used
d) None of the mentioned

Answer: d
Explanation: Power of a one sided test is greater than the power of the associated two sided test.

3. Which of the following value is the most common measure of “statistical significance”?
a) P
b) A
c) L
d) All of the mentioned

Answer: a
Explanation: The P-value is the probability under the null hypothesis of obtaining evidence as extreme or more extreme than would be observed by chance alone.

4. What is the purpose of multiple testing in statistical inference?
a) Minimize errors
b) Minimize false positives
c) Minimize false negatives
d) All of the mentioned

Answer: d
Explanation: A false positive is an error in some evaluation process in which a condition tested for is mistakenly found to have been detected.

5. Point out the wrong statement with respect to FDR.
a) FDR is difficult to calculate
b) FDR is relatively less conservative
c) FDR allows for more false positives
d) None of the mentioned

Answer: a
Explanation: FDR stands for false discovery rate.

6. Which of the following is the oldest multiple testing correction?
a) Bonferroni correction
b) Bernoulli correction
c) Likelihood correction
d) All of the mentioned

Answer: a
Explanation: Bonferroni correction is easy to calculate.

7. The pooled estimator is a mixture of the group variances, placing greater weight on whichever has a larger sample size.
a) True
b) False

Answer: a
Explanation: If the sample sizes are the same the pooled variance estimate is the average of the group variances.

8. Which of the following tool is used for constructing confidence intervals and calculating standard errors for difficult statistics?
a) baggyer
b) bootstrap
c) jacknife
d) none of the mentioned

Answer: b
Explanation: The bootstrap procedure follows from the so called bootstrap principle.

9. Which of the following tool is used for estimating standard errors and the bias of estimators?
a) knitr
b) jackknife
c) ggplot2
d) all of the mentioned

Answer: c
Explanation: jackknife involves resampling data.

10. Power is the probability of rejecting the null hypothesis when it is true.
a) True
b) False

Answer: b
Explanation: Power is the probability of rejecting the null hypothesis when it is false.