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Zorluk: KolayStatistical Sampling and Studies

A forestry service worker randomly selected 8080 oak trees in a state park containing 2,0002,000 oak trees. The worker found that 1212 of the selected oak trees showed signs of a leaf disease. Based on this sample, what is the estimated number of oak trees in the entire state park that show signs of the leaf disease?

Cevap: 300

Cevap

300
Because the sample of 8080 oak trees was selected at random, it can be assumed to be representative of the population of 2,0002,000 oak trees in the state park. The proportion of diseased trees in the sample is 1280=0.15\frac{12}{80} = 0.15. Multiplying this proportion by the total population of 2,0002,000 oak trees yields the estimated total number of diseased trees: 0.15×2,000=3000.15 \times 2,000 = 300.

Adım Adım Çözüm

1
Calculate the sample proportion of diseased trees.
0.15
Dividing the 1212 diseased trees by the sample size of 8080 trees gives the proportion of diseased trees in the sample: 1280=0.15\frac{12}{80} = 0.15.
2
Generalize the sample proportion to the entire population of oak trees in the park.
300
Multiplying the sample proportion of 0.150.15 by the total population of 2,0002,000 oak trees yields the estimated total number of diseased trees: 0.15×2,000=3000.15 \times 2,000 = 300.

Anahtar Kavram

Generalizing results from a representative random sample to estimate a population parameter.
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