10.  If you hear that the support for the President is 50% with the margin of error of plus/minus 2%, then you can interpret this statistical information in light of the concept of

a.  empirical rule

b.  confidence intervals

c.  correlation analysis

d.  central limit theorem

e.  none of the above

Exhibit 12: A sample of 16 information system managers had an average hourly income of $75 and a standard deviation of $5.5. The hourly income is assumed to be normally distributed.

13.  Refer to Exhibit 12. When the 95% confidence interval has to be developed for the average annual income of all system managers, its margin of error is

a.  $1.47

b.  $1.96

c.  $2.93

d.  $5.86

14.  Refer to Exhibit 12. The 95% confidence interval for the average hourly income of all information system managers is

a.  $72.31 to $77.69

b.  $73.31 to $76.35

c.  $72.07 to $77.93

d.  $75.00 to $81.00

15.  A random sample of 100 UT business students revealed that on average they spent 9 hours per week on Facebook. The population standard deviation is assumed to be 2 hours per week. If we want to develop a 95% confidence interval for the average time spent per week on Facebook by all UT business students, the margin of error of this interval is approximately

a.  1.96

b.  0.39

c.  0.20

d.  1.64

16.  We are interested in conducting a study to determine what percentage of eligible voters will support the incumbent governor in the coming election. Recent polls have indicated that the support changes drastically every week. What is the minimum sample size needed to estimate this percentage with a margin of error of 6% and a 99% confidence?

a.  125

b.  461

c.  267

d.  384 

17.  A preliminary sample of holiday shoppers revealed that the standard deviation of the amount of money they are planning to spend on gifts during the coming holiday season is $90. How many holiday shoppers should be sampled in order to estimate the average amount of money spent on gifts by all holiday shoppers with a margin of error of $10 and with a 95% confidence? 

a.  312

b.  100

c.  218

d.  584

Exhibit 13: Most people who bought a new gaming system over the holidays were dissatisfied. In a sample of 900 buyers, 396 buyers were satisfied.

44.  Refer to Exhibit 13. The 90% confidence interval for the true proportion of satisfied buyers is approximately: 

a.  0.4076 to 0.4724

b.  1296.00 to 5040.00

c.  0.4128 to 0.4672

d.  0.2750 to 0.7250

45.  Refer to Exhibit 13. If there were 1 million buyers of the gaming system, the interval for the number of satisfied buyers at 90% confidence is approximately:

a.  407,600 to 472,400

b.  412,800 to 467,200

c.  275,000 to 725,000

d.  0.4076 to 0.4724