Question

Ten years ago, only 20% of the u.s. population consisted of people more than 65 years old. a researcher plans to use a sample of n = 200 people to determine whether the population distribution has changed during the past ten years. if a chi-square test is used to evaluate the data, what is the expected frequency for the older-than-65 category?

Answer 1

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Answer 2

The expected frequency is the sample size n multiplied by the population proportion p obtained from the null hypothesis.:
$n\times p=200\times0.2=40$
The answer is: the expected frequency is 40.