Question

A five-year-old census recorded that 20% of the families in a large community lived below the poverty level. To determine if this percentage has changed, a random sample of 400 families is studied and 66 are found to be living below poverty level.

a) In words, what is the parameter of interest, ??  

b) State the null and alternative hypotheses.

c) Is this a right-tailed, left-tailed, or two-tailed test?  

d) Find ?̂, the estimate for the parameter.

e) Calculate the test-statistic.

f) Find the P-value

g) Make a decision about the null hypothesis at the α = 0.01 significance level. Summarize the results in terms of the problem and alternative.

h) Based on your decision in Part (g), what type of error (I or II) have you possibly made? What is its interpretation within the context of this problem?

Answer 1