When does sampling error occur?
When a sample statistic is not equal to the population parameter as a result of chance factors
If a sample mean is different from a particular population u, we can conclude that the sample mean probably represents some other population or that
the sample mean occurred as a result of sampling error
The key difference between parametric and nonparametric procedures is that parametric procedures
require that certain stringent assumptions be met
Inferential statistics are used to
decide whether sample data represent a particular relationship in the population
Which of the following assumptions is common to all parametric statistics?
The population of dependent scores, which must be interval or ratio scores, forms a normal distribution
Which of the following is correct regarding experimental hypotheses?
They describe the predicted relationship we may or may not find in an experiment
When is a two-tailed test used?
When a relationship is predicted without stating the direction in which the scores will change
When is a one-tailed test used?
When a relationship is predicted and the direction in which the scores will change is predicted
Which of the following is correct regarding statistical hypotheses (null and alternative)?
They describe the population parameters our sample data represent if there is or is not a predicted relationship
Which of the following is correct regarding alternative hypotheses?
They describe the population parameters represented by the sample data if the predicted relationship exists
Which of the following describe(s) the situation if the relationship you are testing in your experiment really exists?
The alternative hypothesis
Which of the following is true of any one-sample experiment?
We must know the population mean under some condition of the independent variable other than the one being tested
The null hypothesis describes the
population parameters represented by the sample data if the predicted relationship DOES NOT exist
Which of the following is called the hypothesis of "no difference"?
The null hypothesis
Which of the following alternative hypotheses would require using a two-tailed test?
Ha: u does NOT = 100
Which hypothesis is actually being tested in statistical hypothesis testing?
The null hypothesis
When can the z-test be used in statistical hypothesis testing?
When the raw score population's standard deviation is known
The population mean for elementary tenacity test (ETT) is 150, with ox = 25. A recent study of elementary school children participating in a school lunch program obtained the following ETT scores. Use two-tailed z-test and a = 0.05
Z crit = + or - 1.96, Z obt = 1.77. Fail to reject Ha
What does the null SAMPLING distribution describe?
The SAMPLING distribution when the null hypothesis is TRUE
In using a sampling distribution of means for statistical hypothesis testing, the mean of the sampling distribution will always equal..
the u described by H0
What does alpha always represent in statistical hypothesis testing?
The relative size of the region of rejection
For a two-tailed test where a = 0.05, z crit is always equal to
+ or - 1.96
What is the Z obt. formula?
Mean (X) - u
____________
Ox
____
square root of N
When statisticians report the results from an experiment are significant, this means the results
are too unlikely to accept as sampling error
When experimental results are significant, this means that the _____ hypothesis has been _____.
the NULL hypothesis has been REJECTED when significant
32) Which of the following statements does not belong?
The change in the dependent scores was produced by significant sampling error
When statisticians report that results are nonsignificant, the results are
not too unlikely to accept as representing the same population
What happens when the experimental results are nonsignificant?
The NULL hypothesis has NOT been rejected
Suppose you have randomly selected high school students to take a course to improve their SAT scores... the mean of their scores is not significantly different from the population mean of SAT scores for those who didn't take course.. Which is best conclus
We have obtained no convincing evidence that the course affects SAT scores
Which of the following statements is true when H 0 is NOT rejected?
The data do not provide sufficient evidence of a relationship in nature
Suppose you conduct an experiment and your Z obt is statistically significant at +3.45. How would you correctly report this result?
Zobt = +3.45; p < 0.05
Suppose you conduct an experiment and the Zobt. is statistically NONsignificant at -0.65. How would you correctly report this?
Z obt. = -0.65; p > 0.05
Suppose that a population is known to have a mean of 80; if a researcher predicts the experimental treatment will produce an increase in the population mean, then the null hypothesis of this test would state
u < or = to 80
For a one-tailed test where the predicted value of the sample mean is larger than the population mean and a = 0.05, Z crit is always equal to...
+1.645
The physical fitness test (National level for girls) shows the national avg. for 10-year old girls on "right-angle push-ups" to be u = 13. Principal Smyth hypothesizes that her girls at Strong School are significantly above the national mean. If the Ox =
Zobt = 1.5, so Principal is wrong
In a one-tailed test, Z obt is significant only if it lies
in the tail of the distribution beyond Z crit and has the same sign as Z crit
When choosing between one-tailed and two-tailed tests,
use a one-tailed test only if you have a convincing reason for predicting the direction
Which of the following accurately defines a Type I Error?
Rejecting the Null (h 0) when the null (H 0) is true
Which of the following represents a Type I Error? We say that something
works when it really doesn't
If you reject the null hypothesis, which of the following may occur?
A correct decision or a Type I error
Which of the following is correct regarding the probability of making a Type I error?
p = a
Which of the following is the probability of avoiding a Type I error?
p = (1 - a)
What happens to the probability of committing a Type I error if the level of significance is changed from a = 0.01 to a= 0.05?
The probability of committing a Type I error will increase
What does it mean when a computer printout reads "p = 0.03"?
The Z obt. falls in the extreme 3% of the sampling distribution and the probability of a Type I error is 0.03
Which of the following accurately defines a Type II error?
Failing to reject the null (H0) when it is false
The power of a statistical test is the probability of
Rejecting a false null (h 0)
Which of the following tests is considered to be more powerful? One or two-tailed?
A one-tailed test