A researcher measures the number of tasks completed by participants during a 5-min multitasking session.If the number of tasks completed is distributed normally as 6.3 ± 1.0 (M ± SD)tasks,then what is the probability that participants completed less than eight tasks?
A) .0446
B) .9554
C) .4554
D) The probability is not listed in the unit normal table.

Question

Quizplus · Accepted Answer

To find the probability that participants completed less than eight tasks, we use the Z-score formula: Z = (X - M) / SD, where X is the value of interest (8 tasks), M is the mean (6.3 tasks), and SD is the standard deviation (1.0 task). Plugging in the values, we get Z = (8 - 6.3) / 1.0 = 1.7. Looking up the Z-score of 1.7 in the standard normal distribution table gives us a probability of approximately 0.9554, meaning there's a 95.54% chance that participants completed less than eight tasks.

A Researcher Measures the Number of Tasks Completed by Participants