QCEVault

Statistical inference — Question 238

Original QCE Vault practice · 5 marks

Q238 · Practice questionTechnology-activeComplex familiar5 marks

QUESTION 238 (5 marks)

A wildlife monitoring budget is $400. Independent measurements with unbiased instrument A have standard deviation 6 and cost $2 each; B has standard deviation 4 and costs $5 each. Use the full budget with one instrument and z=1.96.
a)
Find both sample sizes and 95 percent margins of error to four decimal places.
[3 marks]
b)
Choose the more precise design and explain why smaller individual standard deviation need not win.
[2 marks]
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