stat quiz 9

what is true regarding the student t-distribution?

-The area under the curve is equal to 1.0. -As the number of degrees of freedom increases, the shape of the Student's t-distribution becomes similar to the normal distribution. -It is bell-shaped and symmetrical around the mean of the distribution.

Which one of the following statements is not true regarding the characteristics of the Student's t-distribution?

The shape of the Student's t-distribution is narrower than the shape of the normal distribution.

When calculating a confidence interval for proportions, we assume that sample proportions follow the

binomial distribution

A ________ for the mean is an interval estimate around a sample mean that provides us with a range where the true population mean possibly lies in.

confidence interval

The margin of error can be reduced by reducing the size of the sample.

false

A ________ is a single value that best describes the population of interest.

point estimate

The ________ is used when calculating a confidence interval for the mean using a small sample of size less than 30 with an unknown population standard deviation.

students t-distribution

A 99% confidence interval has a greater chance of "catching" the true population mean when compared to a 90% confidence interval.

true

The point estimate may not equal the true population mean because of the presence of sampling error.

true

The variation in sample means is measured by the standard error of the mean.

true

When substituting the sample standard deviation for the population standard deviation, we can no longer rely on the normal distribution to provide the critical value for the confidence interval.

true