Terms Flashcards
What is kurtosis:
Kurtosis is how peaked or flat a curve is
What is inferential statistics?
Involves Making predictions of values that are not really known.
What is the range.
All the points between x - x on a line. X1-x2 range
What is a percentile?
% of all scores
Quartiles?
A graph displaying all scores into equal quarters
How do you calculate standard deviation?
Find the mean. Then take the raw score, and square each of the raw scores to get the sum of squared numbers. This number you divide by the total number of data points, and subtract that number from the mean^2. This number is variance. Variance is how much each number varies from the mean, on average. Square this number to get standard deviation. SD describes how far away a group of scores differ from the mean.
To calculate variance,
SD^2
Looking for sk- ?
It would show a upward slope to the right showing the mean, median and mode moving up that slope
What about a Sk+
A positive skewed distribution shows a slope curve to the left and the mode, median, mean down the slope, thus its skewed to the positive
What is a normal curve?
A unimodal frequency distribution
What is a Z score?
When you you represent the mean of a group of scores as zero, and you compare that to the average distance between each point from the mean, SD, to scales of 1, 2, 3 +/- to represent points from the mean. which you can refer back to the table in apex. A. The Z score table gives the percentage of cases falling between a given Z score and the mean.
How many % scores fall above a unimodal distribution? z = 0
50%
What is the percentage between to 1 Zscore
34.13
Percentage between 1st and second Z point?
13.59. %
What percentage between the second and third z score,
2.15
To find the percentage of cases falling below a given z score
If Z score is positive, look up the percentage and add 50 %
Is the a score is negative since that number falls to the left 50% subtract that number from 50%
