每日一练 | Data Scientist & Business Analyst 面试题 155

大数据应用 · 公众号 · 大数据 · 2017-08-09 09:07

正文

从6月15日起，数据应用学院将与你一起温习数据科学（DS）和商业分析（BA）领域常见的面试问题。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 55

‍‍DS Interview Questions

How does the KNN algorithm work?‍‍

BA Interview Questions

R language:

Using the following variable:

i=10

x=10

# type a while() or repeat () loop that decreasing i computes x=x/i until i=0.

欲知答案如何？请见下期分解！

Day 54 答案揭晓

DS Interview Questions

What are methods to make a predictive model robust to outliers?

Use a model that is resistant to outliers. Tree-based models are not as affected by outliers as regression models. For statistical tests, choose non-parametric test instead of parametric test

Use a more robust error metric. For instance, use absolute mean difference instead of mean squared error to reduce the effect of outliers

Winsorize the data. Cap the data at a certain threshold

Transform the data. If the data has a pronounced right tail, use log transform

Remove the outliers. If there are very few of outliers and you are certain that they are anomalies not worth predicting

Reference: https://www.quora.com/What-are-methods-to-make-a-predictive-model-more-robust-to-outliers

BA Interview Questions

R language:

Using the following variable:

a=1:10

# type a while () loop that computes a vector x=1 3 6 10 15 21 28 36 45 55

# such that:

# x[1]=a[1]

# x[2]=a[1]+a[2]

# x[3]=a[1]+a[2]+a[3]

# .

a=1:10

i=0

while(i<11){

if(i==1){x[i]=a[i]}

else {x[i]=a[i]+x[i-1]}

i=i+1

}

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