Reaction time for a group of people is normally distributed, with a mean of 0.6 seconds and a standard deviation of 0.2 seconds. Find the probability that an individual selected at random has a reaction time less than 0.9 seconds. Round your answer to four decimal places.
A) 0.4332
B) 0.5668
C) 0.0668
D) 0.9332
E) 0.8664

Question

Reaction time for a group of people is normally distributed, with a mean of 0.6 seconds and a standard deviation of 0.2 seconds. Find the probability that an individual selected at random has a reaction time less than 0.9 seconds. Round your answer to four decimal places. ​
A) 0.4332
B) 0.5668
C) 0.0668
D) 0.9332
E) 0.8664

Quizplus · Accepted Answer

To find the probability that an individual has a reaction time less than 0.9 seconds, we use the Z-score formula: Z = (X - μ) / σ, where X is the value (0.9 seconds), μ is the mean (0.6 seconds), and σ is the standard deviation (0.2 seconds). Plugging in the values gives Z = (0.9 - 0.6) / 0.2 = 1.5. Looking up 1.5 in the Z-table or using a calculator for the cumulative distribution function gives a probability of approximately 0.9332.

Reaction Time for a Group of People Is Normally Distributed