Exam 8: Parameter Estimates

When the null hypothesis is rejected, then we know for certain that

The relationship between the exact value of alpha and the number of degrees of freedom, is that

The estimated standard error of the mean can only be calculated when the entire population of individual scores are available.

Other things being equal, a .99 confidence interval produces a wider interval than when the confidence level is set at .

Other things being equal, an alpha level of .05 should lead to a rejection of the null hypothesis

The average sentence (in months) for homicide is 227 (Gaines & Miller, 2003). A sample of inmates from a certain prison, all of whom having been convicted of homicide, was selected and their sentences calculated. The sentences follow: 200, 225, 197. 256, 300, 158, 220, 226, 230, 215, 237, 223, and 243. -What is the mean of the sample?

Sampling error can be eliminated by using true random sampling.

Whenever the calculated value of t is equal to or greater than the tabled value of t, for a given number of degrees of freedom, then

A significant difference is one that is probably not due to chance.

SPSS Computer Problem The MMPI2 was given to a random sample of 15 men, all of whom had been convicted of auto theft. Their scores on the ASP scale (Anti-Social Practices) were recorded. The population mean on this test is 50.00. The sample scores were as follows: 52,55,48,60,52,49,49,53,56,62,53,56,50,52,53. -Is this sample representative of the population at large? A researcher selects a random sample of 15 young adult females, all of whom were engaged to be married within the next three months. The women were given the MCS (Marriage Commitment Scale), a test with a female population mean of 25. Their scores were: 23,26,27,24,28,19,22,24,27,30,26,28,24,26,29.

A researcher selects a random sample of 15 young adult females, all of whom were engaged to be married within the next three months. The women were given the MCS (Marriage Commitment Scale), a test with a female population mean of 25. Their scores were: 23,26,27,24,28,19,22,24,27,30,26,28,24,26,29. -Is this sample representative of the population at large? The average sentence (in months) for homicide is 227 (Gaines & Miller, 2003). A sample of inmates from a certain prison, all of whom having been convicted of homicide, was selected and their sentences calculated. The sentences follow: 200, 225, 197. 256, 300, 158, 220, 226, 230, 215, 237, 223, and 243.

When an area (between high and low values) of the sampling distribution of means have been bracketed on the basis of a reasonable expectation of containing (estimating) the population mean, then

The estimated standard error of the mean is always used to predict

SPSS Computer Problem The MMPI2 was given to a random sample of 15 men, all of whom had been convicted of auto theft. Their scores on the ASP scale (Anti-Social Practices) were recorded. The population mean on this test is 50.00. The sample scores were as follows: 52,55,48,60,52,49,49,53,56,62,53,56,50,52,53. -Find the single-sample t ratio.

A random sample of 20 fourth-grade students was selected and given the math sub-test of the Peabody Individual Achievement Test (PIAT). The sample mean was found to be 38.07 with an estimated standard error of the mean of 2.11. The population mean was known to be 42.50. Test whether the sample could be representative of the population.

When subjects are selected randomly, then the larger the sample size, the higher the likelihood of the sample mean approaching the population mean.

When estimating the population mean on the basis of the information contained in a single sample, one must at least know

The Type 1 error may never be committed when

For the following set of sample scores, find the estimated standard error of the mean: 25, 21, 17, 16, 15, 14, 11, 8, 7.

Whenever the calculated value of t is less than the tabled value of t (for a given number of degrees of freedom), then