Exam 8: Parameter Estimates

A point estimate predicts a single parameter-mean value.

With a single-sample t ratio, the null hypothesis states that

True random sampling can be guaranteed to eliminate sampling error.

Whenever a sample is selected and measured, one must assume that the sample mean

Parameter estimates are considered to be hypotheses.

A researcher is interested in evaluating a certain brand of radial auto tire. Twenty tires are randomly selected from retail outlets throughout the country, and each is placed on a special machine which rotates the tires at a constant speed (equivalent to 55 miles per hour) against the friction equivalent of a 4000 pound auto being driven on a smooth highway. Each tire is run until there is no tread left. The number of miles (in thousands) were as follows: 40, 30, 32, 35, 39, 35, 31, 36, 37, 35, 34, 35, 37, 34, 36, 38, 35, 36, 35, 36. -Setting alpha at .01, test the hypothesis that this sample of tires could represent a population whose mean was 36.50

Interval estimates, unlike point estimates, are used to predict a single parameter value.

For the following set of sample scores, find the estimated standard error of the mean: 60, 55, 53, 52, 50, 50, 47, 47, 44, 40.

The Type 1 error states the probability of being wrong whenever

Point estimates can never be based on sample values.

For the following set of sample scores, estimate the population mean within a .99 confidence interval: 10, 10, 12, 11, 10.

Reducing the alpha level from .05 to .01 increases the level of confidence.

A point estimate of a population value is referred to as

Regardless of sample size, the degrees of freedom assigned to the single-sample t ratio must remain constant.

Because of sampling error, the point estimate of the population mean may produce an inaccurate prediction.

For the t test, other things being equal, the smaller the value of the alpha error

For the following set of sample scores, find the estimated standard error of the mean: 2, 1, 2, 3, 8, 5, 1.

When the parameter mean is predicted as a single value, the technique employed is called

The true parameter mean may be predicted by using

When we fail to reject null hypothesis, then we know for certain that