ISDS 2000 final (Gabrielle LeBoeuf)

The confidence coefficient equals to

1 - α

For the 90% confidence interval, α= 0.10, α/2 = 0.05

= 1.645

For the 99% confidence interval, α= 0.001, α/2 =0.005

=2.576

Which of the following are components of the formula for selecting n to estimate p?

E zα/2 p

True or false: For a given sample size n and population standard deviation σ, the lower the confidence level 100(1-α)%, the narrower the confidence interval.

True

True or false: the tdf distribution is bell-shaped and symmetric around 0.

True

Suppose you are constructing a confidence interval for the population mean. For a given sample size standard deviation, the width of the interval is wider for a

higher confidence level

In order to construct a confidence interval for μ, the sampling distribution of the estimator Xmust follow or approximately follow a(n) _____________ distribution.

normal

The sampling distribution of the sample proportion can be approximated by a normal distribution when _____.

np ≥ 5 and n(1 - p) ≥ 5

The population mean μ describes a _______________ variable.

numerical or quantitative

When estimating the population mean, the tdf distribution is used when the _________ __________ is unknown.

population parameter

A confidence interval can be interpreted as a

range of values used to estimate an unknown population parameter

When constructing a confidence interval for the population mean, the factors that affect the width of the confidence interval for a given standard deviation are

the confidence level and the sample size.

When rounding a non-integer sample size, you always round ______.

up