True or False: To cut the standard error of the mean in half, the sample size must be doubled.

"Upper Leg Length The upper leg length of 20- to 29-year-old males is approximately normal with a mean length of 43.7 cm and a standard deviation of 4.2 cm.

Source: “Anthropometric Reference Data for Children and Adults: U.S. Population, 1999–2002”; Volume 361, July 7, 2005.

e. A random sample of 15 males who are 20–29 years old results in a mean upper leg length of 46 cm. Do you find this result unusual? Why?"

"Answer the following questions for the sampling distribution of the sample mean shown to the right.

c. If the sample size is n = 16, what is the standard deviation of the population from which the sample was drawn?"

"Answer the following questions for the sampling distribution of the sample mean shown to the right.

b. What is the value of σx̄?"

"Answer the following questions for the sampling distribution of the sample mean shown to the right.

a. What is the value of μx̄?"

The __________ of the sample mean, x̄, is the probability distribution of all possible values of the random variable x̄ computed from a sample of size n from a population with mean μ and standard deviation σ.

Suppose a simple random sample of size n is drawn from a large population with mean μ and standard deviation σ. The sampling distribution of x̄ has mean μx̄ = _________ and standard deviation σx̄ = ________.

Put the following in order from least to greatest.

- t0.10 with 5 degrees of freedom

- t0.10 with 15 degrees of freedom

- z0.10

[NW]

a. Find the t-value such that the area in the right tail is 0.10 with 25 degrees of freedom.

b. Find the t-value such that the area in the right tail is 0.05 with 30 degrees of freedom.