Quiz 1 Vocab

Question 1

Variance

Answer 1

A commonly used measure of dispersion for variables. The variance is calculated by squaring the standard deviation. The variance is based on the square of the difference between the values for each observation and the mean value

Question 2

Treatment

Answer 2

The stimulus given to a dependent variable

Question 3

Sample Size

Answer 3

The number of subjects in a study. Larger samples are preferable to smaller samples, all else being equal

Question 4

Quasi-experimental designs

Answer 4

A type of experimental design in which the researcher does not use random assignment of subjects to groups

Question 5

Systematic Review

Answer 5

A summary of the medical literature that uses explicit methods to perform a comprehensive literature search and critical appraisal of individuals studies and that uses appropriate statistical techniques to combine these valid studies

Question 6

Variable

Answer 6

In research, something that can be changed or altered during an experiment. Each variable that is to be tested would represent a different test condition. For instance, if you were testing the effects of fertilizer on plant growth, the variable might be amount of fertilizer used: such as none, the normal amount, twice the normal amount, and five times the normal amount; A characteristic that can assume any one of several values, for example, cognitive ability, height, aptitude, teaching method

Question 7

Test-Retest Reliability

Answer 7

The degree to which a measure produces consistent results over several administrations

Question 8

P-Value

Answer 8

The probability that the results of a spastically test were due to chance. A p-value greater than .05 is usually interpreted to mean that the results that the results were not statistically significant. Sometimes researchers use a p-value of .01 or a p-value of .10 to indicate whether a result is statistically significant. The lower the p-value, the more rigorous the criteria from concluding significance

Question 9

Probability

Answer 9

The chance that a phenomenon will occur randomly. As a statistical measure, it is shown as p [the “p” factor]; The relative frequency with which a particular event occurs among all events of interest; A description of the likely occurrence of a particular event. Probability is conventionally expressed on a scale from 0 to 1…a rare event has a probability close to 0, a very common event has a probability close to

Question 10

Validity

Answer 10

The degree to which a study accurately reflects or assesses the specific concept that the researcher is attempting to measure. A method can be reliable, consistently measuring the same thing, but not valid; The degree to which data and results are accurate reflections of reality. Validity refers to concepts that are investigated, the people or objects that are studied; the methods by which data are collected; and the findings that are produced

Question 11

Reliability

Answer 11

The degree to which scores obtained with an instrument are consistent measures of whatever the instrument measures; the extent to which a measure, procedure or instrument yields the same result on repeated trials

Question 12

Statistically significant

Answer 12

The conclusion that results are unlikely to have occurred due to sampling error or “chance;” an observed correlation or difference probably exists in the population

Question 13

Random sampling

Answer 13

Methods designed to select a representative sample by using chance selection so that biases will not systematically alter the sample

Question 14

Randomized Controlled Trial

Answer 14

A form of scientific experiment that may be useful when important factors cannot be brought under direct experimental control. In the modern world, the most important examples of RCTs are clinical trials that contrast drugs, surgical techniques, or other medical treatments

Question 15

T-Test

Answer 15

A statistical test that is used to compare the means of two samples or the mean of one sample with some fixed value. The test is appropriate from small sample sizes (less than 30)

Question 16

Paired T-Test

Answer 16

This test is usually used to determine whether an intervention brought about a change in some characteristic of respondents (eg. Respondents’ math knowledge). To perform a paired t-test respondents’ math knowledge would be measured prior to the intervention, then the intervention would be performed (eg. Teaching a class on math), the respondent’s math knowledge would be measured after the intervention. The change from before to after the intervention is used to assess whether the intervention was successful

Question 17

Sampling Distribution

Answer 17

The frequency with which data values appear in the sample. The sampling distribution can be characterized by the mean and the variance of the sample; the theoretical distribution of all possible values of a statistic from all possible samples of a given size selected from a population

Question 18

Purposive Sampling

Answer 18

A sampling strategy in which the researcher selects participants who are considered to be typical of the wider population. Since the sample is not randomly selected, the degree to which they actually represent the population being studied is unknown

Question 19

Normal Distribution

Answer 19

A normal frequency distribution representing the probability that a majority of randomly selected members of a population will fall within the middle of the distribution. Represented by the bell curve; A theoretical “bell-shaped” distribution having a wide application to both descriptive and inferential statistics. It is known or thought to portray many human characteristics in “typical” populations

Question 20

One-Way Anova

Answer 20

A test of whether the mean for more than two groups are different. For example, to test whether the mean income is different for individuals who live in France, England, or Sweden, one would use a one-way ANOVA