ISDS 361 A -- Exam 2 Practice Quizzes

Given an infinite population with a mean of 75 and a standard deviation of 12, the probability that the mean of a sample of 36 observations, taken at random from this population, is less than 78 is: Select one: a. 0.9332 b. 0.5987 c. 1.5000 d. 0.0668

a. 0.9332

For a random sample of size 50 drawn from a population, what theorem or rule is used to determine the type of distribution for the sampling distribution of the sample mean? Select one: a. Central Limit Theorem b. Chebyshev's theorem c. Empirical Rule d. None of the above

a. Central Limit Theorem

If a random sample of size n is drawn from a normal population, then the sampling distribution of the sample mean will be: Select one: a. Normal for all values of n b. Normal only for n > 30 c. Approximately normal for all values of n d. Approximately normal for all values of n > 30

a. Normal for all values of n

The mean of the sampling distribution of the sample mean is: Select one: a. equal to the population mean b. greater than the population mean c. less than the population mean d. not equal to the population mean but the direction cannot be determined

a. equal to the population mean

A sample of 250 observations is selected at random from a n infinite population. Given that the population proportion is 0.25, the standard error of the sampling distribution of the sample proportion will be: Select one: a. 0.5000 b. 0.0274 c. 0.0316 d. 0.0548

b. 0.0274

A random sample of size 49 is taken from a population whose mean is 300 and standard deviation is 21. The mean and the standard error of the sampling distribution of the sample mean, respectively are: Select one: a. 300 and 21 b. 300 and 3 c. 300 and 0.43 d. None of the above

b. 300 and 3

Given an infinite population with a mean of 40 and a standard deviation of 15, a sample of size 100 is taken from it. The standard error of the sampling distribution of the sample mean is: Select one: a. 15-------- b. 0.15------ c. 1.5 d. None of these choices----

c. 1.5

The standard deviation of the sampling distribution of the sample mean is also called Select one: a. central limit theorem b. population standard deviation c. standard error d. None of the above

c. standard error

A sample of size 200 is taken at random from an infinite population. Given that the population proportion is 0.60, the probability that the sample proportion is less than 0.58 is: Select one: a. 0.719 b. 0.580 c. 0.762 d. 0.281

d. 0.281

A sample of size 40 is taken from an infinite population whose mean and standard deviation are 68 and 12 respectively. The probability that the sample mean is larger than 70 equals: Select one: a. P(Z > 70) b. P(Z > 2) c. P(Z > 0.17) d. P(Z > 1.05)

d. P(Z > 1.05)