Statistics
posted by Steven .
Suppose that 7.6% of all people are allergic to the H1N1 vaccine. A sample of 517 people are selected
a. Calculate the probability that less than 8% of the sample will be allergic to vaccine.

Statistics 
MathGuru
Mean = np = 517 * .076 = 39.292
Standard deviation = √npq = √(517 * .076 * .924) = √(36.3058) = 6.025
Note: q = 1  p
x = .08 * 517 = 41.36
Use zscores:
z = (x  mean)/sd
Therefore:
z = (41.36  39.292)/(6.025) = 0.34
Check a ztable for the probability using the zscore calculated above. Remember that the problem is asking "less than" when looking at the table.
I hope this helps.
Respond to this Question
Similar Questions

statistics
A specific study found that the average number of doctor visits per year for people over 55 is 8 with a standard deviation of 2. Assume that the variable is normally distributed. 1. Identify the population mean. 2. Identify the population … 
Economics
I am having problems answering the question below can you please help? 
statistics
A specific study found that the average number of doctor visits per year for people over 55 is 8 with a standard deviation of 2. Assume that the variable is normally distributed. 1. Identify the population mean. The population mean … 
statistics
A hypothetical HIV vaccine trial involving 20,000 participantsâ€”10,000 in the vaccine group and 10,000 in the placebo groupâ€”had the following results: 6.3 infections per 1000 in the vaccine group and 9.0 infections per 1000 in the … 
statistics
One of the ways most people relieve stress is to reward themselves with sweets. According to one study in Food Technology, 46 percent admit to overeating sweet foods when stressed. Suppose that the 46 percent figure is correct and … 
statistics
A poll asked 500 adults if they thought Ontario should produce more, less or maintain current production of ethanol. 160 people responded "more ethanol production" 136 people responded "less ethanol production" 155 people responded … 
Bio
Why do doctors recommend that people get a flu shot each new flu season? 
Chemistry
The National Vaccine Information Center estimates that 90% of Americans have had chickenpox by the time they reach adulthood. We now consider a random sample of 120 American adults: a) Would you be surprised if there were 105 people … 
Statistics
The probability that a randomly chosen person in Botswana is 65 or older is approximately 0.2. a) What is the probability that, in a randomly selected sample of 6 people, exactly 4 of them are 65 or older. If X IS THE NUMBER of people … 
Statistics
In a study by Peter D. Hart Research Associates for the Nasdaq Stock Market, it was determined that 20% of all stock investors are retired people. In addition, 40% of all adults invest in mutual funds. Suppose a random sample of 25 …