The file P02_16.xlsx contains traffic data from 40 weekdays on four variables. Each variable lists the number of arrivals during a specific 5-minute period of the day. For this problem, consider this data set a simple random sample from all possible weekdays.

For each of the four variables, find the sample mean. Round your answers to one decimal place, if necessary.

	Sample Mean
Arrivals 8:00AM to 8:05AM
Arrivals 9:00AM to 9:05AM
Arrivals 10:00AM to 10:05AM
Arrivals 11:00AM to 11:05AM

If each of these is used as an estimate from the corresponding (unknown) population mean, is there any reason to believe that they either underestimate or overestimate the population means?

SelectYes, because these are biased estimates.No, because these are unbiased estimates.Item 5

What are the (approximate) standard errors of the estimates in part a? Round your answers to three decimal places, if necessary.

	Std. Error
Arrivals 8:00AM to 8:05AM
Arrivals 9:00AM to 9:05AM
Arrivals 10:00AM to 10:05AM
Arrivals 11:00AM to 11:05AM

Is it likely that the estimates in part a are accurate to within 1 arrival?

SelectYesNoItem 10

Data:

Day	Arrivals 8:00AM to 8:05AM	Arrivals 9:00AM to 9:05AM	Arrivals 10:00AM to 10:05AM	Arrivals 11:00AM to 11:05AM
1	23	29	9	15
2	45	27	13	14
3	26	19	17	19
4	31	21	21	22
5	36	26	12	14
6	25	34	14	18
7	38	29	16	14
8	29	20	10	16
9	25	18	16	15
10	27	22	16	12
11	31	26	11	15
12	24	17	11	12
13	28	32	15	17
14	43	13	9	17
15	29	26	14	10
16	23	20	14	14
17	26	19	17	19
18	25	22	16	12
19	37	18	19	10
20	29	19	14	13
21	23	23	15	20
22	40	20	13	11
23	30	22	12	18
24	32	20	13	15
25	31	26	15	10
26	25	18	15	15
27	30	21	11	19
28	26	20	18	17
29	26	25	14	15
30	27	24	12	18
31	28	27	17	15
32	31	22	13	11
33	25	20	18	11
34	26	29	12	17
35	25	17	13	13
36	18	23	16	14
37	29	30	15	19
38	28	16	17	11
39	25	25	13	20
40	24	28	9	18