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Suppose the weight of an adult male German Shepherd is normally distributed with a mean of 36.4 kg and a standard deviation of 4.2 kg.

(a) Let X represent the average weight of 35 male adult male German Shepherds selected at random. What is the sampling distribution of X ? Explain.
(b) What is the probability the average weight of 35 randomly selected adult male German Shepherds will be less than 37.5 kg?
(c) If the weights of adult male German Shepherds did not follow a normal distribution, would your answers in parts (d) and (e) still be valid? Explain.

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Final answer:

The sampling distribution of X represents the distribution of sample means from multiple random samples. The probability of the average weight can be found using z-scores and the standard normal distribution. The answers in parts (a) and (b) would still be valid if the weights did not follow a normal distribution with a large enough sample size.

Step-by-step explanation:

(a) Sampling distribution of X:

The sampling distribution of X represents the distribution of the sample means taken from multiple random samples of the same size (in this case, 35 male adult German Shepherds) from a population. The mean of the sampling distribution of X is equal to the population mean (36.4 kg), and the standard deviation of the sampling distribution of X is equal to the population standard deviation divided by the square root of the sample size (4.2 kg / sqrt(35)).

(b) Probability of the average weight:

To find the probability that the average weight of 35 randomly selected adult male German Shepherds will be less than 37.5 kg, we need to convert this value into a z-score. The formula for calculating a z-score is given by z = (X - μ) / (σ / sqrt(n)), where X is the value to be converted, μ is the population mean, σ is the population standard deviation, and n is the sample size. Once we have the z-score, we can use a standard normal distribution table or calculator to find the corresponding probability.

(c) Validity of answers:

If the weights of adult male German Shepherds did not follow a normal distribution, the answers in parts (a) and (b) would still be valid as long as the sample size is large enough (which is typically satisfied with a sample size greater than 30) and the sampling distribution of X can be approximated as a normal distribution by the Central Limit Theorem.

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