PPT-Standard Deviation & Z-Scores

Lets start with an example I divided the class into 2 teams A and B Coincidentally the quiz average for team A is the same as team B 815 So we expect a graph of their scores to be about the same right. DESCRIPTION The formula for the standard deviation is EQ 221 while the formula for the weighted standard deviation is EQ 222 where w is the weight for the ith observation N is the number of nonzero weights and is the weighted mean of the observation Normal distributions show up all over the place.. The standard normal distribution. The standard normal distribution is a . continuous distribution.. It has a mean of 0 and a standard deviation of 1. . The student will be able to: . . find the . variance. of a data set.. . find the . standard deviation. of a data set.. SOL: A.9 . 2009. Variance. Variance. is the average squared deviation from the mean of a set of data. It is used to find the . TIPS FOR APLIA. Developed By: . Ethan Cooper (Lead Tutor) . John Lohman. Michael Mattocks. Aubrey Urwick. Chapter 4: . Variability. Key Terms: Don’t Forget . Notecards. Variability (p. 104). Range (p. 106). First center (expected value). Now - spread. 4.2 (cont.) Standard Deviation of a Discrete Random Variable. Measures how “spread out” the random variable is. Summarizing data and probability. Data. 1. Why understanding probability is important?. What is normal curve. How to compute and interpret z scores.. This week. 2. The chance of winning a lotter. The chance to get a head on one flip of a coin. Standard Deviation. &. The Bell Curve. Standard Deviation. 1st find the . variance. for a set of data. Variance is the average squared deviation from the mean of a set of data. Computing the Variance . Intro to Statistics. What is Normal Distribution?. Modeled by a Bell-shaped curve.. Symmetric about the mean.. Mean (average) and the Median (middle #) are the same number. Or at least very close!!. Can look tall and skinny, short and wide or somewhere in the middle. . Unusual Values. . . Ruisheng. Zhao. OER – . www.helpyourmath.com. . What is the MEAN?. How do we find it?. The mean is the numerical average of the data set, and we use the mean to describe the data set with a single value that represents the center of the data. Many statistical analyses use the mean as a standard measure of the center of the distribution of the data.. Room 315. Gas mileage samples for 250 new Honda Fit are normally distributed, with a mean of 31.3 mpg and a standard deviation of 3.6 mpg. a. Determine the percent of samples that are between 27.7 mpg and 38.5 mpg. Standard Deviation. Standard Deviation – measure . how spread out the data is from the mean. Lower standard deviation:. Data is . closer to the mean. Greater likelihood that the independent variable is causing the changes in the dependent variable. Obj. : The student will be able to . . 1) Calculate standard deviation. . 2) Calculate mean deviation. HWK: Worksheet. Vocab: 1) standard deviation – a measure of how spread out the numbers are. MLA annual meeting, Orlando, Florida. February 24, 2017. Matt Ertz, University of Louisville. matthew.ertz@louisville.edu. Background. Scores of . Scores. Background. Began to appear around 2009. Many score channels decimated by copyright infringement. Bell Ringer Mensa, the largest high-IQ society, accepts SAT scores as indicating intelligence. Assume that the mean combined SAT score is 1500, with standard deviation 300. Jacinto scored a combined 2070.