NOTE: Use hand written formular not computer generated formular

1a). In a computer antiviral campaign in a certain company. Antivirus was administered to812 computers out of a total population of 3248. The number of viral cases is shownbelow

Treatment	Viral	Noviral	total
Antivirus	20	792	812
Noantivirus	220	2216	2436
total	240	3008	3248

Using=0.05level of significance, discuss the usefulness of Antivirus in checking computervirus.

1b.) The amount of time required at a company's customer care desk has been found to beapproximately normally distributed with mean of 3 minutes and a variance of 2500squareseconds. What is the probabilitythatarandomlyselected customerwill:

1. Spendmorethan7 minutes.
2. Takemorethan150 secondsat thedesk.
3. Spendbetween1minute and3minutes.

1c). Family income is believed to be normally distributed with a mean of $25000 and astandarddeviationon $10000.Ifthepovertylevelis$10,000,what percentageof thepopulation lives in poverty? A new tax law is expected to benefit "middle income"families, those with incomes between $20,000 and $30,000. What percentage of thepopulationwill benefit from thelaw?