每日一练 | Data Scientist & Business Analyst & Leetcode 面试题 367

大数据应用 · 公众号 · 大数据 · 2018-05-31 09:19

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Data Application Lab 自2017年6月15日起，每天和你分享讨论一道数据科学(DS)和商业分析(BA) 领域常见的面试问题。

自2017年10月4日起，每天再为大家分享一道Leetcode 算法题。

希望积极寻求相关领域工作的你每天关注我们的问题并且与我们一起思考，我们将会在第二天给出答案。

Day

267

DS Interview Question

Define: quality assurance, six sigma.

BA Interview Question

Can You Provide Us Suggestions for an Effective Use Case Model?

LeetCode Question

Best Time to Buy and Sell Stock II

Description:

Say you have an array for which the ith element is the price of a given stock on day i.

Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). However, you may not engage in multiple transactions at the same time (ie, you must sell the stock before you buy again).

Input: [1,2,3,1,6]

Output: 7

Day

266

答案揭晓

DS Interview Question & Answer

What is the Central Limit Theorem? Explain it. Why is it important?

Answer:

The CLT states that the arithmetic mean of a sufficiently large number of iterates of independent random variables will be approximately normally distributed regardless of the underlying distribution. i.e: the sampling distribution of the sample mean is normally distributed.

- Used in hypothesis testing

- Used for confidence intervals

- Random variables must be iid: independent and identically distributed

- Finite variance

BA Interview Question & Answer

How much time/money is lost due to poorly performed Business Analysis tasks?

Answer:

One could make a case that some of the typical business analysis tasks aren’t that important. Until you apply an associated cost of NOT performing the task, it will be difficult to argue otherwise. Estimate the time and money that is lost on each poorly executed task or the associated cost of not performing the task at all.