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Dell EMC Data Science and BigData Certification Questions and Answers



Question : Which of the following fall under the qualitative data?


: Which of the following fall under the qualitative data?
1. Nominal and Ordinal

2. Nominal and Ratio

3. Ordinal and interval

4. Ratio and interval


Correct Answer : 1
Explanation: Nominal scales are used for labeling variables, without any quantitative value. "Nominal" scales could simply be called "labels."

Example
- Male, Female
- Black, Yellow, Green
- North , South

Ordinal: With ordinal scales, the order of the values is what's important and significant, but the differences between each one is not really known. For example
Today's feeling
- Cold
- Warm
- Hot
- Very Hot





Question : Suppose you have two populations called HEPop and HEPop. You need to check whether two populations are different from each other or not. Which of the following would help in this case?


: Suppose you have two populations called HEPop and HEPop. You need to check whether two populations are different from each other or not. Which of the following would help in this case?
1. You would be using K-means clustering

2. You would be using logistic regression

3. You will be using Hypothesis testing

4. You will be using Linear Regression


Correct Answer : 3
Explanation: Using the Hypothesis testing you can draw inferences on whether or not the two populations like HEPop1 and HEPop2, are different from each other or not. As populations are quite large hence,
you would be doing testing on the Samples. Hence, you will be extracting the samples from the each population and then take their means, which is like u1 and u2. There are following t-tests are available for this
1. Student's t-test
2. Welch's t-test
To apply the t-test, you will be having Hypothesis like Null and Alternate Hypothesis.





Question : You have two populations like HEPop and HEPop, you need to find that both the populations are different from each other or not. Which of the following is correct Hypothesis in this case?


: You have two populations like HEPop and HEPop, you need to find that both the populations are different from each other or not. Which of the following is correct Hypothesis in this case?
1. Null Hypothesis : mean of(HEPop1) = mean of (HEPop2)
Alternate Hypothesis: mean of (HEPop1) <> mean of (HEPop2)

2. Null Hypothesis : mean of(HEPop1) <> mean of (HEPop2)
Alternate Hypothesis: mean of (HEPop1) = mean of (HEPop2)

3. Null Hypothesis : mean of(HEPop1) <> mean of (HEPop2)
Alternate Hypothesis: mean of (HEPop1) <> mean of (HEPop2)

4. You cannot use mean of population for inferring the Population equality


Correct Answer : 1
Explanation: To check whether two populations are equal or not you can use the Hypothesis testing and in the Hypothesis testing you will be taking mean of the sample (If population is very large) and then
take the mean of the samples. Hence, you can use mean of population as well as mean of samples. Hence, option-4 is out.
Now we need to consider the two Hypothesis as below
Null Hypothesis: Mean of both the population/Samples are almost equal
Alternate Hypothesis: Mean of both the populations/Samples are not equal
If you accept the Null Hypothesis, it means you are saying means are almost equal. And if means are almost equal then population is same. If we reject the Null Hypothesis then it means we are saying mean of both the
populations are not equal (Which means accepting the alternate Hypothesis). Hence, option-1 is correct.
And to test the difference in the means you can use Student's t-test or Welch's t-test.



Related Questions

Question : A disk drive manufacturer has a defect rate of less than .% with % confidence. A quality
assurance team samples 1000 disk drives and finds 14 defective units. Which action should the
team recommend?

 : A disk drive manufacturer has a defect rate of less than .% with % confidence. A quality
1. A larger sample size should be taken to determine if the plant is operating correctly
2. The manufacturing process is functioning properly and no further action is required
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4. There is a flaw in the quality assurance process and the sample should be repeated




Question : What is a core deliverable at the end of the analytic project?
 : What is a core deliverable at the end of the analytic project?
1. An implemented database design
2. A whitepaper describing the project and the implementation
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4. The training materials



Question : Your organization has a website where visitors randomly receive one of two coupons. It is also
possible that visitors to the website will not receive a coupon. You have been asked to determine if
offering a coupon to visitors to your website has any impact on their purchase decision.
Which analysis method should you use?


 : Your organization has a website where visitors randomly receive one of two coupons. It is also
1. K-means clustering
2. Association rules
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4. One-way ANOVA



Question : You have been assigned to run a logistic regression model for each of countries, and all the
data is currently stored in a PostgreSQL database. Which tool/library would you use to produce
these models with the least effort?
 : You have been assigned to run a logistic regression model for each of countries, and all the
1. RStudio
2. MADlib
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4. HBase


Question : Imagine you are trying to hire a Data Scientist for your team. In addition to technical ability and
quantitative background, which additional essential trait would you look for in people applying for
this position?


 : Imagine you are trying to hire a Data Scientist for your team. In addition to technical ability and
1. Communication skill
2. Scientific background
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4. Well Organized




Question : What describes the use of UNION clause in a SQL statement?
 : What describes the use of UNION clause in a SQL statement?
1. Operates on queries and potentially decreases the number of rows
2. Operates on queries and potentially increases the number of rows
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4. Operates on both tables and queries and potentially increases both the number of rows and columns