Exam 2

A sample statistic is an unbiased point estimate of a population parameter if the mean of the populations of all possible values of the sample statistic equals the population parameter.

True

The standard deviation of all possible sample proportions increases as the sample size increases.

False

The Central Limit Theorem states that as sample size increases, the population distribution more closely approximates a normal distribution.

True

The sample standard deviation s is an unbiased estimator of the population
standard deviation σ

False

Sampling error occurs because of incomplete information

True

The normal probability distribution is a discrete probability distribution.

False

The z value tells us the number of standard deviations that a value x is from the mean

True

If the random variable x is normally distributed, 68.26 percent of all possible observed values of x will be within two standard deviations of the mean

False

A random sample of size 36 is taken from a population with mean 50 and
standard deviation 5. What is μx?

50

The mean of a standard normal distribution is always equal to ____________.

0

If the random variable of x is normally distributed, _____ percent of all
possible observed values of x will be within two standard deviations of the
mean.

95.44

____________ values of the standard deviation result in a normal curve that is
wider and flatter.

Larger

The fill weight of a certain brand of adult cereal is normally distributed with a
mean of 910 grams and a standard deviation of 5 grams. We calculated the
value of z for a specific box of this brand of cereal, and the z value was
negative. This negative z value indicates that:

The fill weight is less than 910 grams.