A type of small snail is very widespread in Japan, and colonies of the snails that are genetically similar have been found very far apart. Scientists wondered how the snails could travel such long distances. A recent study provides the answer. Biologist Shinichiro Wada fed 174 live snails to birds and found that 26 of the snails were excreted live out the other end. The snails apparently are able to seal their shells shut to keep the digestive fluids from getting in.
(a) What is the best point estimate for the proportion of all snails of this type to live after being eaten by a bird?
(b) Figure 3.20 shows a bootstrap distribution based on this sample. Estimate the standard error.

Figure 3.20

(c) Use the standard error from part (b) to find and interpret a 95% confidence interval for the proportion of all snails of this type to live after being eaten by a bird.
(d) Using your answer to part (c), is it plausible that 20% of all snails of this type live after being eaten by a bird?

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100 # sample = 1000 mean = 0.15 st. dev. = 0.028 Right Tail Left Tail Two-Tail 90 80 70 (a). (b). (c). (d). 30 20 10 0.14 I 0.16 0.08 0.10 0.12 0.18 0.20 0.22 0.24 0.15