#4: c-Chart

Each day, a factory counts the number of machine failures and wants to plot the number of failures/day on a c-chart. A c-chart is appropriate, because each day there may be multiple machine failures (nonconformances). The data has been collected in the Microsoft Excel Online file below. Open the spreadsheet and perform the required analysis to answer the questions below.

table {mso-displayed-decimal-separator:"\."; mso-displayed-thousand-separator:"\,";} tr {mso-height-source:auto;} col {mso-width-source:auto;} td {padding-top:1px; padding-right:1px; padding-left:1px; mso-ignore:padding; color:black; font-size:10.0pt; font-weight:400; font-style:normal; text-decoration:none; font-family:Arial, sans-serif; mso-font-charset:0; text-align:general; vertical-align:bottom; border:none; white-space:nowrap; mso-rotate:0;} .xl18 {color:windowtext; text-align:right; vertical-align:middle; background:#A9D08E; mso-pattern:black none;} .xl20 {color:windowtext; text-align:right; background:#A9D08E; mso-pattern:black none;} .xl22 {color:windowtext; text-align:center; vertical-align:middle; background:#A9D08E; mso-pattern:black none;} .xl23 {color:windowtext; vertical-align:middle; background:#A9D08E; mso-pattern:black none;} .xl26 {color:windowtext; font-weight:700; text-align:center; vertical-align:middle; background:#A9D08E; mso-pattern:black none;} .xl27 {color:windowtext; text-align:center; vertical-align:middle; background:#9BC2E6; mso-pattern:black none;} .xl28 {color:windowtext; vertical-align:middle; background:#9BC2E6; mso-pattern:black none;} .xl29 {color:windowtext; font-weight:700; vertical-align:middle;} .xl30 {color:windowtext; vertical-align:middle;} .xl33 {color:#C65911; vertical-align:middle;} .xl34 {color:windowtext; text-align:right; vertical-align:middle;} .xl35 {color:windowtext; font-weight:700; font-family:Arial, sans-serif; mso-font-charset:204; vertical-align:middle;} .xl37 {color:windowtext; background:#F4B084; mso-pattern:black none;} .xl38 {color:windowtext; text-align:center; vertical-align:middle;} .xl41 {color:windowtext; text-align:left; vertical-align:middle;}

c-Chart
			Formulas
Number of samples	25
Average (c-bar)			#N/A
Standard deviation			#N/A
LCLc			#N/A
UCLc			#N/A
	Number of
Unit	Nonconformances		LCLc	CL	UCLc
1	3
2	0
3	1
4	3
5	0
6	0
7	3
8	4
9	4
10	3
11	1
12	2
13	4
14	2
15	0
16	0
17	1
18	1
19	6
20	1
21	0
22	1
23	1
24	0
25	5
Use the area below to construct a line chart for a c-chart.

Questions

1. What is the average number of failures per day? Round your answer to three decimal places.

2. What is the standard deviation? Do not round intermediate calculations. Round your answer to five decimal places.

3. What is the lower control limit, LCL_c? Do not round intermediate calculations. Round your answer to three decimal places.

4. What is the upper control limit, UCL_c? Do not round intermediate calculations. Round your answer to three decimal places.