The mean ! The tail (right or left) is the skew. The hump is the modal (right or left) Negative is and positive is Mode Median Mean Frequency (%) 1 2 3 4 5 6 7 8 Length of Hospital Stay (days) Standard deviation is Standard deviation is only used when the the typical distance that each data point is from the mean. We aren't going to find standard deviation of a population because if we know the whole group we won't make inferences about it. We find standard deviation of a sample (no Greek) Calculating Standard Deviation The number of data points Each of the values of the data The mean of Normal Distribution Curve Thought What % of the Area is under the whole curve? N is the number in the sample. Why the n-1 because it is more accurate, because of degrees of freedom. Markers activity or prom dates! Another explanation of degrees of freedom: Joe takes 5 tests he must get a 70% earn the c get the degree! 71, 68, 67, 71, _(no freedom must be to get the C) Z score is how many standard deviations you are from the mean. Z score at the mean is zero because you are _from the mean.4. The temperature is recorded at 60 airports in a region. The average temperature is 67 degrees Fahrenheit with a standard deviation of 5 degrees. What is the z-score for a temperature of 68 degrees? . Z 5. A group of friends compares what they received while trick or treating. They find that the average number of pieces of candy received is 43, with a standard deviation of 2. What is the z-score corresponding to 20 pieces of candy? - 1. 916 6. The mean growth of the thickness of trees in a forest is found to be .5 cm/ year with a standard deviation of .1 cm/year. What is the z-score corresponding to 1 cm/year? 5