Prepare for and practice interview questions from PCS Global Tech across topics like SQL, Machine Learning, Algorithms and more.

PCS Global Tech Interview Questions

A/B Testing

Algorithms

Analytics

Machine Learning

Probability

Product Metrics

Python

Statistics

PCS Global Tech Interview Guides

<p>Let’s say you work for a social media company that has just done a launch in a new city. Looking at weekly metrics, you see a slow decrease in the average number of comments per user from January to March in this city.</p>

<p>The company has been consistently growing new users in the city from January to March.</p>

<p>What are some reasons why the average number of comments per user would be decreasing and what metrics would you look into?</p>


<p>What metric could be used to measure if active users are still engaging on the platform despite an overall decrease in the average number of comments per user?</p>

What metric could be used to measure if active users are still engaging on the platform despite an overall decrease in the average number of comments per user?

Decreasing Comments

How would you investigate a decline in the average number of comments per user?

<p>An online marketplace company has introduced a new feature that allows potential buyers and sellers to conduct audio chats with each other prior to transacting.</p>

<p>Let’s say we have two tables that represent this data.</p>

<p><strong>Example:</strong></p>

<p><strong>Input:</strong></p>

<p><code>chats</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>buyer_user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>seller_user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>call_length</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>call_connected</code></td>
<td>INTEGER</td>
</tr>
</tbody>
</table>
<p><code>marketplace_purchases</code> table</p>

<table>
<thead>
<tr>
<th>Column</th>
<th>Type</th>
</tr>
</thead>

<tbody>
<tr>
<td><code>id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>buyer_user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>seller_user_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>item_id</code></td>
<td>INTEGER</td>
</tr>

<tr>
<td><code>purchase_amount</code></td>
<td>FLOAT</td>
</tr>
</tbody>
</table>

<ol>
<li>How would you measure the success of this new feature?</li>
<li>Write a query that can represent if the feature is successful or not.</li>
</ol>


How would you measure the success of an online marketplace introducing an audio chat feature given a dataset of their usage?

Audio Chat Success

<p>Let’s say that your company is running a standard control and variant AB test on a feature to increase conversion rates on the landing page. The PM checks the results and finds a .04 p-value.</p>

<p>How would you assess the validity of the result?</p>
