Exam 8: Parameter Estimates

The concept of the standard error of the mean indicates that the actual population mean can never be a true parameter.

Estimating the value of the population mean on the basis of the sample mean alone produces a(n)

Rejecting Ho when in fact we should have failed to reject it, causes the

The Type 1 error is committed when here is a failure to reject Ho when in fact it should have been rejected.

When sample scores are compared with a population value that is known to be true, we are able to use the one-sample t ratio.

A random sample of 61 fifth-grade students was selected and given the Stanford-Binet IQ test. The mean score for the sample was 97, with an estimated standard error of the mean of 2.43. Estimate whether the sample mean could be representative of a population whose mean is 100.

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. -Estimate the population mean within a confidence interval of .99.

The standard error of the mean may never be negative.

The concept of the standard error of the mean implies that the estimated population standard deviation must yield a value which over-estimates the true mean.

The estimated standard error of the mean may be calculated on the basis of the information contained in a single random sample.

For the following set of sample scores, find the estimated standard error of the mean: 8, 6, 7, 7, 3, 1, 8.

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. -Estimate the population mean within a confidence interval of .95.

For a given value for the sample's standard deviation, increasing the sample size increases the value of the standard error of the mean.

A random sample of 30 infants (age 12 months) was selected and given a Motoric Development test. The mean score for the sample was at the 13.20 month level. The estimated standard error of the mean was 1.25. Estimate whether the mean test age of the sample could be representative of a population whose mean test age is 12 months. 113

The alpha level specifies the probability of being correct when rejecting null.

The techniques of inferential statistics are based on a probability model, and may sometimes lead to inaccurate predictions

Other things being equal, increasing the sample size, decreases the width of the confidence interval.

When alpha is set at .05 and Ho is rejected, then the probability is

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. -Find the mean mileage for this sample.

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. -Find the estimated standard error of the mean.