In: Statistics and Probability
Question 1
Office Support, Inc. provides on-site repair for most large photocopy machines. It currently has five trained repair teams that it sends out on an on-call basis. Since the company advertises one-day service, it will not accept more than five requests for service per day. Two months ago, the vice president started considering expanding the workforce. At that time he asked the call desk to record the actual calls for each of the next 40 days. The data to respond to the questions below are provided in the Office worksheet. Define the random variable x as the number of service calls per day. Clearly x is a discrete random variable.
4 points: Use built-in Excel functions to find the minimum and maximum values of x. That is, find the minimum number and maximum number of service calls per day over the 40 day period.
Place the minimum in cell E2.
Place the maximum in cell E3.
4 points: Based on the minimum and maximum number of service calls per day in the sample of 40 days, specify the complete range of x. That is, make a list of all possible outcomes of x under the column labeled x starting in cell G2.
9 points: Using the built-in Excel function named
COUNTIF, calculate the count (frequency) of each
outcome (x) in the sample. In general, your function with its
arguments will appear as
“=COUNTIF(argument 1, argument 2),” where
argument 1 is the data range and argument 2 is a
cell reference containing a specific outcome value. Start by
finding the count for x = 0, then finding the count for all other
outcomes. The values will be under the column labeled
“Count.”
In the first unused cell following the last count value (from above), use Excel’s built-in SUM function to calculate the total count (frequency). For example, if the count cells went from H2:H7, enter the sum in cell H8. Format the sum cell (box, color, etc.) to highlight that it contains the sum of the values above it.
|
Range of x | Value |
Min(x) = | 0 |
Max(x) = | 6 |
Day | Number of Service Calls | Range of x | Value | 1a | x | Count | P(x) | ||||||||
1 | 2 | Min(x) = | 0 | 0 | 3 | 0.075 | 0 | ||||||||
2 | 1 | Max(x) = | 6 | 1 | 4 | 0.1 | 0.1 | ||||||||
3 | 3 | 2 | 10 | 0.25 | 0.5 | ||||||||||
4 | 2 | 3 | 8 | 0.2 | 0.6 | ||||||||||
5 | 4 | 4 | 7 | 0.175 | 0.7 | ||||||||||
6 | 3 | 5 | 6 | 0.15 | 0.75 | ||||||||||
7 | 2 | 6 | 2 | 0.05 | 0.3 | ||||||||||
8 | 0 | E(x) = | 2.95 | Var(x) = | 2.55 | ||||||||||
9 | 5 | StdDev(x) = | 1.60 | ||||||||||||
10 | 2 | Grader | |||||||||||||
11 | 5 | 1b | |||||||||||||
12 | 3 | 1c | |||||||||||||
13 | 4 | 1d | |||||||||||||
14 | 2 | 1e | |||||||||||||
15 | 6 | 1f | |||||||||||||
16 | 1 | 1g | |||||||||||||
17 | 0 | 1h | |||||||||||||
18 | 3 | ||||||||||||||
19 | 5 | ||||||||||||||
20 | 2 | ||||||||||||||
21 | 4 | ||||||||||||||
22 | 3 | ||||||||||||||
23 | 5 | ||||||||||||||
24 | 1 | ||||||||||||||
25 | 5 | ||||||||||||||
26 | 2 | ||||||||||||||
27 | 2 | ||||||||||||||
28 | 4 | ||||||||||||||
29 | 3 | ||||||||||||||
30 | 6 | ||||||||||||||
31 | 2 | ||||||||||||||
32 | 4 | ||||||||||||||
33 | 0 | ||||||||||||||
34 | 4 | ||||||||||||||
35 | 5 | ||||||||||||||
36 | 1 | ||||||||||||||
37 | 3 | ||||||||||||||
38 | 4 | ||||||||||||||
39 | 2 | ||||||||||||||
40 | 3 |