1.Reports from a new system set up to monitor Internet use by company employees indicate that 145 out of a random sample of 1,100 employees at a corporation accessed Internet sites that were clearly not related to their jobs over the last week. On average, employees who accessed non-job related sites spent 4.8 hours per week at such sites with a standard deviation of 2.1 hours.

(a) Give a 95% confidence interval for the percentage of employees at the corporation who access non-job related sites.

(b) Briefly explain in one short sentence how to interpret this interval.

(c) Statistics show that about 10% of people nationwide access non-job related sites at work. Is this company really any different from the national statistics?

(d) Can we say that roughly 95% of people at this company spent in the range of 4.8 hours plus or minus 4.2 hours on non job-related web sites?

2.Where do CFOs get their money news? According to Robert Half International, 47% get their money news from newspapers, 15% get it from communication/colleagues, 12% get it from television, 11% from the Internet, 9% from magazines, 5% from radio, and 1% don't know. Suppose a researcher wants to test these results. She randomly samples 67 CFOs and finds that 40 of them get their money news from newspapers. Does the test show enough evidence to reject the findings of Robert Half International?

3.Management of a soft-drink bottling company wants to develop a method for allocating delivery costs to customers. Although one cost clearly relates to travel time within a particular route, another cost variable reflects the time required to unload the cases of soft drink at the delivery point. A sample of 20 deliveries within a territory was selected. The delivery times (in minutes) and the number of cases delivered were recorded in the file WK3_X2.xls. An analyst computes the delivery time per case delivered and averages these to get 0.33 minutes. Using this he gives an estimated delivery time of 50 minutes for 150 cases to be delivered. Is this a reasonable delivery time? Explain why or why not. Looking at the data in the file, can you give a better estimate? Make sure that you justify your estimate.

(Excel_WK3_X2.xlsl)

Customer Number of cases Delivery Time

1 52 32.1

2 64 34.8

3 73 36.2

4 85 37.8

5 95 37.8

6 103 39.7

7 116 38.5

8 121 41.9

9 143 44.2

10 157 47.1

11 161 43.0

12 184 49.4

13 202 57.2

14 218 56.8

15 243 60.6

16 254 61.2

17 267 58.2

18 275 63.1

19 287 65.6

20 298 67.3

4.A manufacturer of cereal has a machine that, when working properly, puts 20 ounces of cereal on average into a box with a standard deviation of 1 ounce. Every morning workers weigh 25 filled boxes. If the average weight is off by more than 1% from the desired 20 ounces per box, company policy requires them to re-calibrate the machine. In a sample of 100 days where the machine is working properly all day on how many the days is it expected the machine will be re-calibrated. Show Work.