Exam 9: The Single-Sample T Test

Imagine the average time to complete a 4-year bachelor degree is actually 4.7 years based on national data.You collect data on the 68 psychology students who started school during the same semester as you, finding an average time to complete at 4.3 years with a standard deviation of 0.6 years.What would be the effect size associated with a single-sample t test?

Many companies that manufacture lightbulbs advertise their 60-watt bulbs as having an average life of 1000 hours.A cynical consumer bought 30 bulbs and burned them until they failed.He found that they burned for an average of M = 1233, with a standard deviation of s = 232.06.What statistical test would this consumer use to determine whether the average burn time of lightbulbs differs significantly from that advertised?

The first step in conducting the single-sample t test includes:

A researcher is comparing two groups.The population mean from which the samples come is known, but not the population standard deviation.Which test should be used?

The formula for the degrees of freedom for the single-sample t test is:

Which report of statistical results is in appropriate APA format?

Two types of graphs that make it easy to see the distribution of two variables side-by-side are the:

A dot plot allows us to _____, while a stem-and-leaf plot does not.

Use the following to answer questions This figure represents the distribution of the percent of state residents living in a metropolitan area for all 50 U.S.states and Washington D.C. -(Figure: Percent Metropolitan) The plot in the figure is a:

The standard deviation of the sample is used to estimate the standard deviation of the population.

Degrees of freedom for the single-sample t test is N - 2.

Why does one divide by N - 1 rather than by N when estimating a population standard deviation from the sample standard deviation?

The second step in conducting the single-sample t test involves _____ and _____.

The correct formula for the upper bound of a confidence interval for a single-sample t test is:

Assume that the national credit card interest rate is 12.83 percent.A study of 81 college students finds that their average interest rate is 15 percent with a standard deviation of 8.7 percent.What is the 95 percent confidence interval for this single-sample t test?

Effect size measures have a different meaning for the t test than they do for the z test.

The single-sample t test compares the mean of a sample to a population for which the mean but not the standard deviation is known.

The t statistic indicates the:

The numerator (top portion) of the ratio for calculating all t statistics contains:

What is the correct formula for using the sample standard deviation to estimate the population standard deviation?