Statistics - Mathematics

Statistics - Mathematics

QUESTION 1

In its standardized form, the normal distribution

has a mean of 0 and a standard deviation of 1.

has a mean of 1 and a variance of 0.

has an area equal to 0.5.

cannot be used to approximate discrete probability distributions.

QUESTION 2

True or False: Any set of normally distributed data can be transformed to its standardized form.

True

False

QUESTION 3

Suppose the ages of students in Statistics 101 follow a skewed-right distribution with a mean of 23 years and a standard deviation of 3 years. If we randomly sampled 100 students, which of the following statements about the sampling distribution of the sample mean age is incorrect?

The mean of the sampling distribution is equal to 23 years.

The standard deviation of the sampling distribution is equal to 3 years.

The shape of the sampling distribution is approximately normal.

The standard error of the sampling distribution is equal to 0.3 years.

QUESTION 4

True or False: The standard error of the mean is also known as the standard deviation of the sampling distribution of the sample mean.

True

False

QUESTION 5

A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall. Fifteen credit card accounts were randomly sampled and analyzed with the following results (Steel & Torrie,1960).. Assuming the distribution of the amount spent on their first visit is approximately normal, what is the shape of the sampling distribution of the sample mean that will be used to create the desired confidence interval for µ?

Approximately normal with a mean of $50.50

A standard normal distribution

A t distribution with 15 degrees of freedom

A t distribution with 14 degrees of freedom

QUESTION 6

True or False: The confidence interval estimate of the population proportion is constructed around the sample proportion (Schervish,1997).

True

False

QUESTION 7

How many Kleenex should the Kimberly Clark Corporation package of tissues contain? Researchers determined that 60 tissues is the average number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: . Suppose the test statistic does fall in the rejection region at a = 0.05. Which of the following conclusion is correct?

At a = 0.05, there is not sufficient evidence to conclude that the average number of tissues used during a cold is 60 tissues.

At a = 0.05, there is sufficient evidence to conclude that the average number of tissues used during a cold is 60 tissues.

At a = 0.05, there is not sufficient evidence to conclude that the average number of tissues used during a cold is not 60 tissues.

At a = 0.05, there is sufficient evidence to conclude that the average number of tissues used during a cold is not 60 tissues.

QUESTION 8

True of False: Suppose, in testing a hypothesis about a proportion, the Z test statistic is computed to be 2.04. The null hypothesis should be rejected if the chosen level of significance is 0.01 and a two-tailed test is ...