Pinterest measurement tech 电面

是和measurement team 得 HM直接面得

1.        Background.
就是介绍一下经历，木有问问题。

2.        Talk about a project. What is the purpose of the project? Who are the stakeholders? How do you perform data completeness and quality tests? How do you deal with missing values? What model do you build? How do you deal with imbalanced data set? What is the criterion?
前面都是关于project得一些follow up question, 所以感觉还行。后面问了一个问题，

Given a single decision tree and two variables, variable A has high variance, variable B has low variance, which variable will first be used to split?
我第一反应是木有直接关系，感觉split feature应该和loss function 有关，而不是和feature 本身得variance有关。想了一下，我就说应该是 high variance把， 应为 decision tree tries to maximize the impurity decrease at each split.

3.        (SQL) 原题

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Curated Interview Questions from Top Companies

Given a single decision tree and two variables, variable A has high variance, variable B has low variance, which variable will first be used to split?

感觉这题描述不太清楚。我觉得应该是问: Spliting using variable A gives high variance (其实应该是分割后两个child node的weighted variance), spliting using variable B gives low vairance, which variable should we use to split?

应该选B，就是split之后variance低的。当然是希望split之后的子树越pure越好，pure = low vairance

参考https://youtu.be/i5wGWV5H7oM

应该选variance低的呀
Here are the steps to split a decision tree using reduction in variance:
For each split, individually calculate the variance of each child node
Calculate the variance of each split as the weighted average variance of child nodes
Select the split with the lowest variance
Perform steps 1-3 until completely homogeneous nodes are achieved

Frances0412 发表于 2019-8-22 02:21
请问take home是什么题啊？你还有data可以分享下嘛。。。

有点久远了，记不太清了。。。大概是一个估计每个广告商每个月会赞助多少钱，大概有5个variable把，我先做了一下classification， 选取了部分数据， 然后再做的model

谢谢分享！

楼主是面的DS还是ML呀？

maohappy2013 发表于 2019-4-30 04:15
楼主是面的DS还是ML呀？

DS measurement team

感谢分享～楼主有后续吗

Dangdang001 发表于 2019-5-1 00:53
感谢分享～楼主有后续吗

上周刚做了take home, 等结果中。。。

miaogemiao 发表于 2019-5-1 03:56
上周刚做了take home, 等结果中。。。

他们家是一轮电面+一轮take home，然后再onsite吗？

好奇是楼主自己投的还是hr联系的呀？我也投了但是没有反应。。

cindy410xi 发表于 2019-8-18 06:56
好奇是楼主自己投的还是hr联系的呀？我也投了但是没有反应。。

自己网投的

Frances0412 发表于 2019-8-18 03:12
他们家是一轮电面+一轮take home，然后再onsite吗？

HR 是这样告诉我的，然而我挂在了take-home 上。。。