Question 1

Which t distribution most resembles the Z distribution?

Accepted Answer

As the degrees of freedom (df) increase, the t distribution approaches the Z distribution. A t distribution with df = 130 closely resembles the Z distribution.

Question 2

We are constructing confidence intervals for the mean number of women employed in software companies. We have a random sample of 30 companies, and the population's standard deviation is unknown. What would be the correct degrees of freedom for constructing the confidence intervals?

Accepted Answer

When the population standard deviation is unknown and a sample is used, the degrees of freedom for constructing confidence intervals is calculated as the sample size minus one, which is 30 - 1 = 29.

Question 3

What graphical tool is used to depict confidence intervals?

Accepted Answer

Error bar graphs are used to depict confidence intervals, showing the variability of data and the uncertainty in measurements.

Question 4

Which of the following provides the most conservative estimate of P_u?

Accepted Answer

The answer of Which of the following provides the most...

Question 5

What will happen to the confidence interval if we change it from the 99% confidence level to the 95% level?

Accepted Answer

When the confidence level is decreased from 99% to 95%, the confidence interval becomes narrower because we are accepting a higher level of uncertainty.

Question 6

A research teams wishes to estimate the interval of ì with a sample of size 200. Without altering their sample size, what must the researchers do to obtain a very narrow confidence interval?

Accepted Answer

The answer of A research teams wishes to estimate the...

Question 7

Describe what three changes must be made when constructing confidence intervals when the standard deviation of the population is estimated from s compared to when ó is known.

Accepted Answer

The answer of Describe what three changes must be made...

Question 8

Of the 700 respondents of a random sample, 89 said they were retired.

Accepted Answer

The answer of Of the 700 respondents of a random...

Question 9

Of the 668 respondents, 432 said that they are concerned about the environment. Ten years ago, in response to the same question, 378 of 703 respondents expressed concern for the environment.
Has environmental concern risen over the 10-year period?

Accepted Answer

The answer of Of the 668 respondents, 432 said that...

Quiz 6: Estimation Procedures for Sample Means and Proportions