Chapters 6 and 8

The mean of the t distribution is a) 0 b) .5 c) 1 d) problem specific

a) 0

In an interval estimation, as the sample size becomes larger, the interval estimate a) becomes narrower b) becomes wider c) remains the same, because the mean is not changing d) gets closer to 1.96

a) becomes narrower

A normal probability distribution a) can have mean of any numerical value b) needs to have a mean of 0 c) has a standard deviation of 0 d) must have a standard deviation of 1 and a mean of 0

a) can have a mean of any numerical value

The ability of an interval estimate to contain the value of the population parameter is described by the a) confidence level b) degree of freedom c) precise value of the population mean d) point estimate

a) confidence level

A normal probability distribution a) is a continuous probability distribution b) is a discrete probability distribution c) can be continuous or discrete d) must have a standard deviation of 1

a) is a continuous probability distribution

In a standard normal distribution, the range of values of Z is from a) minus infinity to infinity b) -1 to 1 c) 0 to 1 d) -3.09 to 3.09

a) minus infinity to infinity

As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution a) becomes larger b) becomes smaller c) stays the same d) fluctuates

b) becomes smaller

An estimate of a population parameter that provides an interval of values believed to contain the value of the parameter is known as the a) confidence level b) interval estimate c) margin of error d) point estimate

b) interval estimate

The center of a normal curve is a) always equal to zero b) is the mean of the distribution c) cannot be negative d) is the standard deviation

b) is the mean of the distribution

For a given confidence level and when standard deviation is known, the margin of error in a confidence interval estimate a) varies from sample to sample of the same size b) is the same for all samples of the same size c) increases as the sample size increases d) is independent of sample size

b) is the same for all samples of the same size

The value added to and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the a) confidence level b) margin of error c) parameter estimate d) planning value

b) margin of error

In a standard normal distribution, the a) mean and the standard deviation are both 1 b) mean is 0 and the standard deviation is 1 c) mean is 1 and the standard deviation is 0 d) mean and the standard deviation can have any value

b) mean is 0 and the standard deviation is 1

The margin of error in an interval estimate of the population mean is a function of all of the following except a) alpha b) sample mean c) sample size d) variability of the population

b) sample mean

When s is used to estimate standard deviation, the margin of error is computed using the a) normal distribution b) t distribution c) mean of the sample d) mean of the population

b) t distribution

A negative value of z indicates that a) the number of standard deviations of an observation is to the right of the mean b) the number of standard deviations of an observation is to the left of the mean c) a mistake has been made d) that data has a negative mean

b) the number of standard deviations of an observation is to the left of the mean

The z score for the standard normal distribution a) is always equal to 0 b) can never be negative c) can be either negative or positive d) is always equal to the mean

c) can be negative or positive

The t distribution is a family of similar probability distributions, with each individual distribution depending on a parameter known as a) finite correction factor b) sample size c) degrees of freedom d) standard deviation

c) degrees of freedom

Which of the following is a characteristic of the standard normal probability distribution a) the mean, median and mode are not equal b) the distribution is not symmetrical c) the standard deviation must be 0 d) the standard deviation must be 1

c) the standard deviation must be 1

For the normal probability distribution, the area to the right of the mean is a) 1 b) 3.09 c) 1.96 d) 0.5

d) 0.5

The standard deviation of a normal distribution a) is always 0 b) is always 1 c) can be any value d) cannot be negative

d) cannot be negative

If the mean of a normal distribution is negative a) the standard deviation must also be negative b) the variance must also be negative c) a mistake has been made in the computations, because the mean of a normal distribution cannot be negative d) none of these alternatives are correct

d) none of these alternatives are correct

The probability that the interval estimation procedure will generate an interval that does NOT contain the actual value of the population parameter being estimated is the a) proportion estimate b) margin of error c) confidence coefficient d) same as alpha

d) same as alpha

Which of the following is NOT a characteristic of the normal probability distribution a) the mean, median and mode are not equal b) the distribution is symmetrical c) the mean of the distribution can be negative, zero, or positive d) the standard deviation must be 1

d) the standard deviation must be 1

Larger values of the standard deviation result in a normal curve that is a) skewed to the right b) skewed to the left c) narrower and more peaked d) wider and flatter

d) wider and flatter