? asked in 科學數學 · 1 decade ago

# ~急~求一題standard deviation標準差

Creek Ratz is a very popular restaurant located along the coast of northern Florida. They serve a variety of steak and seafood dinners. During the summer beach season, they do not take reservations or accept ”call ahead” seating. Management of the restaurant is concerned with the time a patron must wait before being seated for dinner. Listed below is all the wait times, in minutes, for the tables seated last Saturday night. (Round mean and standard deviation to 2 decimal places.)

28 39 23 67 37 28 56 40 28 50

51 45 44 65 61 27 24 61 34 44

64 25 24 27 29

The median of the times is____minutes.

The mean of the times is_____minutes.

The range of the times is____ minutes.

The standard deviation is_____ minutes.

*有詳細過程解釋*

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• 1 decade ago

First arrange the numbers in ascending order.

23 24 24 25 27 27 28 28 28 29

34 37 39 40 44 44 45 50 51 56

61 61 64 65 67

(a) The median is the middle (13th out of 25) number = 39 minutes

(b) The mean is the average = Sum / 25 = 40.84 minutes

(c) The range is the maximum - minimum = 67 - 23 = 44 minutes

(d) Standard deviation = √[∑(x - mean)^2 / 25]

= √{[(23 - 40.84)^2 + (24 - 40.84)^2 + ... + (67 - 40.84)^2]/25}

= 14.55 minutes