A survey selects a simple random sample of n 500 people fro

A survey selects a simple random sample of n = 500 people from a town of 55,000. The sample shows an average of 2.30 health problems per person (standard deviation = 1.65). True or false: it is reasonable to assume that the sampling distribution of mean will vary according to a Normal distribution.

True or False

Suppose that asthma affects 1 in 20 children in a population. You take a simple random sample of 50 children from this population. Can the normal approximation to the binomial be applied under these conditions?

Select one:

Yes

No

There were 101,098 women in a California county for the year 2006. A study of 1000 women\'s records was randomly selected from this county. 12 breast cancers were reported for the year 2006. The incidence rate is approximately 120 per 100,000. If you want to use this number to make a statement about breast cancer in California state, this incidence rate 120 per 100,000 is

Select one:

parameter

statistic

both

neither

Solution

True. Sample size is large so we can assume normal distribution.

--------------------

No

Here we have p=1/20=0.05 and n=20. Here we have

np=2.5

and

n(1-p)=47.5

Since np is less than 5 so the normal approximation to the binomial cannot be applied under these conditions.

--------------

Statistics because whole population is not considered.