Posted by **Maggie** on Monday, June 25, 2007 at 4:18pm.

Hello,

I have a few questions I'm working on for Statistics hw. Here's one of them - please help me, I'm stuck.

It is known that 2% of the population has a general injection allergy. Suppose the Health Dept. randomly selected 250 individuals from the population and there were 7 people known to have the allergy .

a. construct a 99% confidence interval for the population proportion p.

I can't figure this out because i don't have the numbers or the standard deviation. i was thinking p(1-p)/n, which gives .0089 when I find the root. then is it P(Z=.15) = P(z=14.61?) The problem is that I can't find this number on my table of z scores.

b. what is the probability that the proportion in the sample that has the injection allergy will be as great as 4%?

Is this the same as above but P(Z=.04)?

Thank you for you help!

Formula:

CI99 = p + or - (2.58)(sqrt of pq/n)

...where sqrt = square root; p = x/n; q = 1 - p; and + or - 2.58 represents the 99% confidence interval using a z-table.

With your sample data:

CI99 = 7/250 + or - (2.58)[sqrt of (7/250)(243/250)/250]

Convert fractions to decimals.

I'll let you take it from there.

Perhaps someone else can help you with part b.

## Answer this Question

## Related Questions

- English - Hello Can you please come up with a few questions on the following ...
- m/c - Which of the following refers to when a researcher gathers data from a ...
- Statistics - Hello Can you help me It is reported that 72% of working women use...
- statistics - We believe that 77% of the population of all Business Statistics I ...
- Statistics - 3. A professor is interested in whether there is a difference in ...
- statistics - A recent national survey reported that the general population gave ...
- precal - The Census Bureau reported that the population of the United States in ...
- statistics - a. A statistics practitioner randomly sampled 100 observations from...
- statistics - a.a statistics practitioner randomly sampled 100 observations from ...
- writing - Which of the following statements is not a general rule for using ...

More Related Questions