Question

You are given data from a company that recently laid off a large number of workers. The data includes the following variables:

Age of the employee

Number of years of education

Marital status (1=married/0=single)

Number of years that the employee worked for the company

Was a manager (1=yes/0=no)

Was in sales (1=yes/0=no)

Was primary earner in the family (1=yes/0=no)

95% confidence interval for proportion of employees who were in sales before they were laid off.

What do the confidence intervals tell you about the typical employee who got laid off?

Age	Educ	Married	Primary earner	length of employment	Manager	Sales
30	14	1	1	1	0	0
27	14	1	0	6	0	0
32	10	0	1	11	0	0
44	11	1	0	2	0	0
21	14	1	1	2	0	0
26	13	1	0	7	1	0
26	15	1	0	6	0	0
33	13	0	1	6	0	0
27	12	1	1	8	0	0
33	12	0	1	2	0	0
20	11	1	0	1	0	0
35	7	1	1	6	0	0
36	17	0	1	9	1	0
26	12	1	1	8	0	0
36	15	0	1	8	0	0
38	16	1	1	11	0	1
34	13	0	1	13	0	0
27	19	1	0	8	0	0
44	13	1	0	22	0	0
45	15	1	1	6	0	0
28	17	0	1	3	0	1
25	10	1	1	1	0	0
31	15	1	0	12	0	0
23	15	1	0	2	0	0
24	13	1	1	7	0	0
62	13	0	1	8	0	0
31	16	1	0	11	0	0
48	18	0	1	30	0	0
35	18	1	1	5	0	0
33	14	0	1	6	0	1
46	15	0	1	6	0	0
35	8	0	1	6	0	0
32	9	1	1	13	0	0
40	17	1	0	8	1	0
23	12	1	1	1	0	0
36	16	0	1	8	0	1
33	12	1	0	10	0	1
32	16	0	1	11	0	0
62	15	1	0	16	0	1
29	14	1	1	12	0	0
45	12	1	0	17	0	0
38	15	0	1	6	0	1
40	8	1	1	16	0	1
42	13	1	0	2	1	0
45	16	1	1	22	0	0
39	11	1	1	4	0	0
27	15	1	0	10	0	1
42	14	1	1	6	1	0
31	10	1	1	8	0	0
33	13	1	1	8	0	0

Answer 1

95% confidence interval for proportion of employees who were in sales before they were laid off.

What do the confidence intervals tell you about the typical employee who got laid off?

One-Way Summary Table
Count of Sales
Sales	Total	Percentage
0	41	82.00%
1	9	18.00%
Grand Total	50

Confidence Interval Estimate for the Proportion
Data
Sample Size	50
Number of Successes	9
Confidence Level	95%
Intermediate Calculations
Sample Proportion	0.18
Z Value	1.9600
Standard Error of the Proportion	0.0543
Interval Half Width	0.1065
Confidence Interval
Interval Lower Limit	0.0735
Interval Upper Limit	0.2865

95% CI for proportion = (0.0735, 0.2865).

We are 95% confident that proportion of all employees who were in sales before they were laid off falls in the interval (0.0735, 0.2865).