Exam 7: Statistics and Parameters

The standard deviation of the population of individual Digit Span scores is 3.00. (The Digit Span test is a sub-test of the Wechsler IQ test). A random sample of 20 subjects yielded a mean Digit Span score of 7.25. a. Calculate the standard error of the mean. b. Test the hypothesis, using the z test, that the sample could be representative of a population whose mean is known to be 10.00.

Any sample which contains fewer than 50% of the total population

When a sample mean is greater than the true, population mean, the resulting difference is called

The Central Limit theorem states that the sampling distribution of means is normal in shape.

A researcher in the area of IQ wishes to measure a sample of children using the WISC III. The standard deviation on the WISC-III is 15. How large a sample should be selected if the researcher wishes to be .95 accurate to within 5 IQ points?

The standard deviation of the population of elementary school math- achievement scores is 7.78. A random sample of 20 elementary school children was selected and yielded a mean achievement score of 80.04. a. Calculate the standard error of the mean. b. Use the z test to establish whether this sample could be representative of the general population of elementary school children whose mean math achievement score is known to be 78.00.

With a normal distribution, if the standard deviation in the population of individual verbal SAT scores is 100, then the Range should approximate_________

Sampling error is assumed to result

The standard error of the mean must equal

Random sampling occurs when

When the population mean differs from the sample mean, the result is called

With true random sampling, every observation in the population has an equal chance of being selected.

The standard deviation of the population of adult female spine lengths is .92 inches. A random sample of 40 women was selected and the mean spine length was found to be 26 inches. a. Calculate the standard error of the mean. b. Use the z test to determine whether this sample could be representative of a the general population of women whose mean spine length is known to be 24 inches.

The techniques of inferential statistics are designed to yield

If the mean IQ of all Omega University students was equal to 115, and a small sample of students was selected from the population whose mean IQ was 120, then this difference of 5 points would equal

The standard deviation of the population of individual scores is 15. A random sample of 10 scores yields a mean of 100. Calculate the standard error of the mean.

Whenever the sampling error is consistently in one direction, the result is

When comparing the size of the standard error of the mean with the size of the standard deviation of the underlying distribution of individual scores,

In order to calculate the z test, one must know

An entire group of persons, things or events having at least one trait in common defines the