Final answer:
No, waiting 38 minutes for the bus is not considered unusual because it is less than two standard deviations above the mean, which is only a little over one standard deviation from the average wait time of 25 minutes.Therefore correct option is B
Step-by-step explanation:
The question asks if it is unusual to have to wait 38 minutes for the bus to arrive, given an average wait time of 25 minutes and a standard deviation of 12 minutes. To determine if 38 minutes is an unusual wait time, we can calculate how many standard deviations away from the mean this time is.
To calculate the number of standard deviations, we use the formula: Z = (X - μ) / σ, where Z is the Z-score, X is the value in question, μ is the mean, and σ is the standard deviation.
Plugging in the numbers, we get Z = (38 - 25) / 12, which is 13 / 12 or approximately 1.08. This value of 1.08 indicates that 38 minutes is a little over one standard deviation away from the mean.
Since 38 minutes is less than two standard deviations above the mean, it is not considered unusual, as a common rule of thumb in statistics is that a data point is not unusual if it is within two standard deviations of the mean. Thus, the correct answer to the question is:
d) No, because 38 minutes is less than two standard deviations above the mean.