Question

A company claims its new keyboard increases typing speed, citing that employees who used the new keyboard typed faster than those who did not. Which of the following, if true, most weakens this conclusion?

• A. The new keyboard costs more than the old one.
• B. Typing speed matters for the company's productivity.
• C. A few employees disliked the new keyboard.
• D. The employees who used the new keyboard were chosen because they were already the fastest typists.

Hint:

Was the faster group already fast before using the keyboard?

Answer 1

The Correct Option is D

Step 1: Identify the reasoning.
The company concludes the keyboard causes higher speed because its users typed faster.
Step 2: Attack the cause.
If the fast users were already the fastest typists before getting the keyboard, their speed comes from their own skill, not the keyboard. This removes the causal link.
Step 3: Reject the rest.
Cost, importance of speed, and a few dislikes do not challenge the cause-effect claim. Option 4 weakens most.