Suppose that an accounting firm does a study to determine the time needed to complete one person's tax forms. It randomly surveys 175 people. The sample mean is 23.8 hours. There is a known population standard deviation of 6.2 hours. The population distribution is assumed to be normal. A) Find the following: i) The sample mean ? ii) The population standard deviation σ iii) The sample size n B) Let X be the time needed to complete one person's tax forms, and ?̅ the mean time needed to complete tax forms from a sample of 175 customers. Note that before the sample is drawn ?̅ is a normal random variable but after the sample is drawn ? is an actual number. i) What is the distribution for the random variable ?̅ ? ii) What is the mean for ?̅ ? iii) What is the standard deviation for ?̅ ?
Problem 2: Suppose that an accounting firm does a study to determine the time needed to complete one person's tax forms. It randomly surveys 175 people. The sample
A) Find the following:
i) The sample mean ?
ii) The population standard deviation σ
iii) The
B) Let X be the time needed to complete one person's tax forms, and ?̅ the
mean time needed to complete tax forms from a sample of 175 customers.
Note that before the sample is drawn ?̅ is a normal random variable but
after the sample is drawn ? is an actual number.
i) What is the distribution for the random variable ?̅ ?
ii) What is the mean for ?̅ ?
iii) What is the standard deviation for ?̅ ?
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