A z-score of z = -2.00 indicates a position in a distribution ____.
A) above the mean by 2 points
B) above the mean by a distance equal to 2 standard deviations
C) below the mean by 2 points
D) below the mean by a distance equal to 2 standard deviations
For a distribution of scores, which of the following z-score values represents the location closest to the mean?
A) z = +0.50
B) z = +1.00
C) z = -1.00
D) z = -2.00
A z-score of z = +3.00 indicates a location that is ____.
A) near the center of the distribution
B) slightly above the mean
C) far above the mean in the extreme right-hand tail of the distribution
D) The location depends on the mean and standard deviation for the distribution.
Last week Sarah had exams in Math and in Spanish. On the math exam, the mean was m = 40 with s = 5, and Sarah had a score of X = 45. On the Spanish exam, the mean was m = 60 with s = 8 and Sarah had a score of X = 68. For which class should Sara expect the better grade?
C) The grades should be the same because the two exam scores are in the same location.
D) There is not enough information to determine which is the better grade.
A random sample requires that ____.
A) every individual has an equal chance of being selected
B) the probabilities cannot change during a series of selections
C) there must be sampling with replacement
D) All of the other choices are correct.
A jar contains 10 red marbles and 20 blue marbles. If you randomly select one marble from the jar, what is the probability of getting a red marble?
The standard deviation of the distribution of sample means is called ____.
A) the expected value of M
B) the standard error of M
C) the sample mean
D) the central limit mean
The symbol that corresponds to the standard error of M is ____.
A) s M
A population has m = 80 with s = 8. The distribution of sample means for samples of size n = 4 selected from this population would have a standard error of ____.
If random samples, each with n = 4 scores, are selected from a normal population with m = 80 and s = 10, then the distribution of sample means will have a standard error of ____.
A) 2.5 points
B) 5 points
C) 10 points
D) 80 points