SOLUTION: Based on historical information, it is assumed that no more than 35% of aggregate household income is spent on food. A researcher believes that this proportion is now lower wit

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Question 918897: Based on historical information, it is assumed that no more than 35%
of aggregate household income is spent on food. A researcher believes
that this proportion is now lower with increase in real wages. A study of
82 persons show that 37 spend less than 35%, is there reason at the
5% significance level to believe that the proportion is now lower?

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Based on historical information, it is assumed that no more than 35%
of aggregate household income is spent on food. A researcher believes
that this proportion is now lower with increase in real wages. A study of
82 persons show that 37 spend less than 35%, is there reason at the
5% significance level to believe that the proportion is now lower?
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Ho: p >= 0.35
Ha: p < 0.35 (claim)
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p-hat = 37/82 = 0.82
test stat:: z(0.82) = (0.82-0.35)/sqrt[0.35*0.65/82] = 15.56 (that's enormous)
---
p-value = p(z > 15.56) = 0
----
Conclusion:: Since the p-value is less than 5%, reject Ho.
The test results support the claim.
Cheers,
Stan H.
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