Welcome to the first weekly #WhatsYourMBAiQ question. If you've stumbled here thinking you've found another source of GMAT or GRE questions, check again. At MBA iQ, we help aspiring MBAs reach their potential by accelerating MBA readiness.

What's readiness and why is it important?

When our founder Devi started at Harvard Business School, she was rudely surprised by how little she knew about what to expect. She had the grades, the GMAT score, the experience, but as a successful CPA, she had some blind spots in her business acumen. Unfortunately, you don't know you're unprepared until it's too late, and once you start that cycle of catching or leveling up, it's a tough cycle to break. Devi learned that the best way to mitigate against that feeling is to be prepared.

MBA iQ lays the foundation upon which you can build in B school and helps you to discover and mitigate against those blind spots before you start.

But let's take a closer look at our challenge question:

This question is about data analysis of package deliveries. If you work in operations or have a strong statistics background, this is probably a language you speak, but if you're a marketing director at an NGO or non-profit, you might be wondering if we're teaching a foreign language class.

Question

A delivery company defines a "defect" as a package delivered later than the promised delivery time. Management wants to monitor the proportion of packages delivered per week beyond the promised delivery time. Management is willing to sample 150 packages per week and determine which of these packages are "defects." Which type of control chart would be most appropriate based on what the company wants to monitor and the data to be collected?

a. X bar-chart
b. R-chart
c. p-chart
d. np-chart

Answer & Explanation

Choice (c) is the correct answer. A p-chart is expressed as a fraction or a percent of nonconforming units or number of defects in a sample. Choice (a) is incorrect because an X bar-chart is used to determine a process average. This isn't relevant because we want to know the percentage of defects and not the average number of defects. Choice (b) is incorrect because an R-chart deals with process variability or range, which would mean looking at the range of the number of defects over time. The question asks for the proportion out of 150 packages. Choice (d) is incorrect because an np-chart shows the number of nonconforming units. The question asked for a proportion or percentage and not an absolute number.

Hint: If some of these terms like average, range or absolute number are feeling a little foreign, a quick review of basic stats vocabulary might help.

In most MBA statistics courses, you'll learn about various statistical tools that are available to managers to understand business issues – in this case defects in package deliveries.

If you're looking to expand your knowledge further, check out MBA iQ's multi-modular online learning solution that covers core business knowledge, analytical skills and other topics crucial for MBA success. Our best-in-class modules provide the tools to strengthen foundational knowledge so students can hit the ground running on Day 1 of a rigorous MBA program.

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