enc 510 midterm

Failing to reject a null hypothesis when the research hypothesis is true is called:

Type II error

Approximately what percentage of scores fall within one standard deviation of the mean in a normal distribution? A. 68% B. 95% C. 99% D. 34%

A. 68%

Which of the following is NOT a measure of variability? A. Median B. Standard deviation C. Range D. Variance

A. Median

The number of problems correct on an objective test would be an example of what level of variable? A. Ratio B. Nominal C. Interval D. Ordinal

A. Ratio

Failing to reject a null hypothesis when the research hypothesis is true is called: A. effect size B. a Type II Error C. a Type I Error D. statistical power

B. a Type II Error

Consider this example: A scoop of water drawn from a fish tank full of tropical saltwater fish is used to determine the exact salt content of the water. The scoop of water represents the: A. Parameter B. Population distribution C. Sample D. Population

C. Sample

If a researcher concludes that the null hypothesis should be rejected and the results are "statistically significant at a .05 level," we can conclude that: A. The researcher would expect to be wrong .05 times out of 100. B. The researcher would expect to incorrectly retain a false null 5 times out of 100. C. The researcher would expect randomness to explain such an extreme difference 5 times out of 100. D. The researcher would expect a 5% chance of committing a Type II error.

C. The researcher would expect randomness to explain such an extreme difference 5 times out of 100.

Which statement about the median is false? A. Even with skewed distributions, the median splits the distribution in half. B. The median splits the distribution in half. C. When a distribution contains an even number of values, its median is replaced by the mean. D. The median will be equivalent to both the mean and the mode in a normal distribution.

C. When a distribution contains an even number of values, its median is replaced by the mean.

A Type I Error is the result of: A. improper measuring techniques on the part of the researcher B. failing to reject the null hypothesis when, in fact, it is true C. incorrectly rejecting the null hypothesis D. None of the above

C. incorrectly rejecting the null hypothesis

In a distribution of z-scores, the mean is always: A. 10 B. 1 C. 50 D. 0

D. 0

Which statement regarding skewed distributions is TRUE? A. Z-scores help to describe the spread of a skewed distribution. B. If a distribution is negatively skewed, the mode will always be a higher value than the median. C. If a distribution is positively skewed, the mean will always be a lower value than the median. D. If a distribution is negatively skewed, the mean will always be a lower value than the median.

D. If a distribution is negatively skewed, the mean will always be a lower value than the median.

The standard deviation is: A. The square root of the variance B. A measure of variability C. An approximate indicator of how numbers vary from the mean D. All of the above

D. all the above

Which is a discrete variable? A. weight B. height C. grade point average D. number of left-handed male cousins

D. number of left-handed male cousins

What is the median of the following set of scores? 18, 6, 12, 10, 14 ? A. 18 B. 10 C. 14 D. 12

D.12

The goal of ___________ is to focus on summarizing and explaining a specific set of data.

descriptive statistics

The mean and the mode for a distribution of scores would be the same if the distribution is:

normal