STT 200 EXAM QUESTIONS AND
ANSWERS
What is the primary purpose of a 95% confidence interval for a mean? - Answer- to
estimate a population mean
The confidence level for a confidence interval for a mean is - Answer- the probability the
procedure provides an interval that covers the population mean.
Which of the following will not result in paired data? - Answer- One random sample is
taken, and a variable is recorded for each individual, but then units are categorized as
belonging s to one population or another.
Which of the following statements is most correct about a confidence interval for a
mean? - Answer- It provides a range of values, any of which is a good guess at the
possible value of the population mean.
When constructing a confidence interval for the differences in two populations means, it
is appropriate to use the pooled standard error only when - Answer- the population
standard deviations can be assumed to be equal.
Which one of the following ways of collecting data would result in two independent
samples? - Answer- A sample of English majors is measured for stress before taking an
important exam. A sample of engineering majors is also measured for stress before
taking their important exam.
Which of the following is an example of a difference in two proportions based on
independent samples? - Answer- A random sample of 800 adults in the US in 1999 was
asked if they support the legalization of marijuana, and another random sample of 800
adults was asked the same question in 2009. The difference in the proportions of adults
who supported it in 1999 and 2009 is found.
Which of the following statements is correct about a parameter and a statistic
associated with repeated random samples of the same size from the same population?
- Answer- Values of a statistic will vary according to the sampling distribution for that
statistic.
The distinction between a sampling distribution and confidence interval is: - Answer- A
sampling distribution gives possible values for a sample statistic when the population
ANSWERS
What is the primary purpose of a 95% confidence interval for a mean? - Answer- to
estimate a population mean
The confidence level for a confidence interval for a mean is - Answer- the probability the
procedure provides an interval that covers the population mean.
Which of the following will not result in paired data? - Answer- One random sample is
taken, and a variable is recorded for each individual, but then units are categorized as
belonging s to one population or another.
Which of the following statements is most correct about a confidence interval for a
mean? - Answer- It provides a range of values, any of which is a good guess at the
possible value of the population mean.
When constructing a confidence interval for the differences in two populations means, it
is appropriate to use the pooled standard error only when - Answer- the population
standard deviations can be assumed to be equal.
Which one of the following ways of collecting data would result in two independent
samples? - Answer- A sample of English majors is measured for stress before taking an
important exam. A sample of engineering majors is also measured for stress before
taking their important exam.
Which of the following is an example of a difference in two proportions based on
independent samples? - Answer- A random sample of 800 adults in the US in 1999 was
asked if they support the legalization of marijuana, and another random sample of 800
adults was asked the same question in 2009. The difference in the proportions of adults
who supported it in 1999 and 2009 is found.
Which of the following statements is correct about a parameter and a statistic
associated with repeated random samples of the same size from the same population?
- Answer- Values of a statistic will vary according to the sampling distribution for that
statistic.
The distinction between a sampling distribution and confidence interval is: - Answer- A
sampling distribution gives possible values for a sample statistic when the population
