Fast-food restaurants spend quite a bit of time studying the amount of time cars spend in their drive-throughs. certainly, the faster the cars get through the drive-through, the more the opportunity for making money. qsr magazine studied drive-through times for fast-food restaurants and found wendy’s had the best time, with a mean time spent in the drive-through of 138.5 seconds. assuming drive-through times are normally distributed with a standard deviation of 29 seconds, answer the following.

(a) management wants to set a wait time over which a customer will not have to pay for their food. of course, management wants to set that wait time to the 99th percentile. find the x for the 99th percentile. (hint: 99% = 0.9900). round to the nearest whole second. sullivan, michael iii. fundamentals of statistics: #40 (ch 7.2). pearson education. kindle edition.

For the 99th percentile, we have X = 206 seconds.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean and standard deviation , the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

99th percentile:

Value of X when Z has a pvalue of 0.99. So we use

For the 99th percentile, we have X = 206 seconds.

the answer is 375 miles

step-by-step explanation:

i believe it's a.

i'm not sure on this one, most likely correct.