2.3 Flashcards
Describe mean, median, and mode
Mean - adding all scores and dividing by the # of scores
Median - middle score after scores are arranged highest to lowest
Mode - Score that occurs most frequently
What is standard deviation used for?
If a given score is a certain number of SD’s around the mean, we can determine what % of the other scores it exceeds.
Inferential stats and most common use
Attempts to deduce the properties of a large population based on the results from a small sample of that population
Calculate the probability that a given research result could have arisen by chance
How can probability of chance results be lowered?
If the difference between the two groups is large
If the variability within each group is small
If the number of indivs in each group is large
What is statistical significance? What is its standard?
1) The probability that accidental fluctuations could produce the same results
2) If statistical sig is p
Define descriptive stats
Mathematical summaries of results
When is the mean of a set of data most useful?
When scores approximate the normal distribution/curve
What is normal distribution/curve?
Symmetrical frequency of scores clustered around the mean.
There is always 50% of scores at or below the mean, and there is always 50% of scores at or above the mean.
When is the median most useful?
Whenever the population distribution is far from symmetrical (ie large outliers)
What is the range of a distribution?
A statement of the highest and lowest scores
Define standard deviation
A measurement of the amount of variation among scores in a normal curve
T or F - The closer the scores to the mean, the larger the SD
False - SD is small
T or F - The standard deviation is small when scores are spread out from mean
False - SD is large
What does the p is p
Probability
What is the 95% confidence interval?
The range within which the true population mean lies, with 95% certainty
