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7-94.
  1. Cups of Coffee Sold

    1

    22

    37

    5

    22

    38

    7

    23

    38

    12

    24

    40

    12

    25

    41

    12

    26

    41

    12

    26

    42

    12

    29

    47

    14

    29

    47

    16

    30

    49

    17

    30

    51

    19

    31

    52

    20

    32

    55

    21

    33

    55

    21

    35

    59

    22

    36

    76

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    Katelyn records the number of cups of coffee sold at her coffee shop each hour during a 48‑hour time period.

  2. Katelyn then sorts the data and makes the following histogram: Homework Help ✎

    1. Katelyn decides to model her sales with a normal distribution, but Duncan thinks that this is not a good idea. What advice would you give Katelyn about using a normal model?

    2. Katelyn needs to sell more than 15 cups of coffee per hour to make a profit. What percentile is 15 cups per hour? Explain the percentile to Katelyn in terms of profits.

    3. Duncan thinks Katelyn should expand her business. He estimates that if Katelyn hires another server and adds more tables and equipment, she will need to sell 48 cups of coffee per hour to make a profit. What percentile does 48 cups sold represent? Use the percentile to explain to Duncan whether or not expansion is a good idea.

The data should be symmetric, single-peaked, and bell-shaped. Is it?

Look at the data. How many data points sold less than 15 cups of coffee?
Compare this to the total number of data points.

Use the same method as you did in part (b).
Note that this time it may be easier to count data points that sold more than 48 cups.