Formulas
x = x
n
Median= n+1/2
Lower Quartile= .25 (n) Upper Quartile=.75 (n)
IQR= Q3Q1
Coefficient of Variation =
s
x
Sample Variance (X) n X n 1
2
(100)
2
Sample Standard Deviation
(X) n X
2
2
n1 Regression Analysis
slope =
( X )( Y ) XY - N
X
Pearso
Review: Quiz #3
X of Z
1) Average attendance in the National Basketball Association (NBA) is 18,000 with a standard deviation of 2,500. If the Golden State Warriors want to be in the top 70 percent of attendance of NBA teams, approximately how many people
Confidence Intervals with a Single Sample Using Either Z or T Distribution I. An international dormitory wants to see how long, on average, its members have been in the United States. Out of 105 people in the dorm, 18 were sampled and averaged 4.5 years i
Quiz #5
^ 1) Y = 6.5 + 2.25(x) is known as the:
a) regression equation b) intercept c) coefficient of determination d) R
2
2) What is the explanation of the slope for the above equation?
^ a) with each unit increasein x, there would be a negative 2.25 dec
HypothesisTesting
There is widely held belief that men are at a greater advantage in terms of salary than women in technological fields. The average of engineering salaries of men is known with men making, on average, an introductory salary of $50,000 wit
Why Use Z scores?
Percentages can be used to compare different scores, but don't convey as much information Z scores also called standar di zed scor es, making scores from different distributions comparable; Ex: You get two different scores in two differe
Demystifying RegressionAnalysis: X and Y Together
1) Santa has come to us becausehe has a problem. It seemsthat his younger reindeers have been hard to motivate, and they aren't as knowledgeable or productive as the older reindeer. Santa, unfortunately, h
(X) 2 N X2 N
Population Variance 2
(X) 2 n X2 n1
Sample Variance= s2
(X) 2 N X2 N
Population Standard Deviation=
(X) 2 n X2 n1
Sample Standard Deviation= s
Below is a table to distinguish between four Measures of variability: Population variance, Sa
Sampling Distribution(excerpted from Learning to Live With Statistics: From Concepts to Practice)
What is a sampling distribution? A sampling distribution is the hypothetical distribution of a statistic taken from a large number of random samples (of a gi
Pie Chart Directions Using Excel: Naturalized BY Region of World
1) Select data of interest. An easy way to do this is to highlight first cell you want to use, hold down the shift key, select last cell and data of interest will be ready for use. 2) Select
Working with the Normal Distribution and z scores: Practice Problems 1) Assume that professors' evaluation scores are normally distributed with a mean of 100 and a standard deviation of 25 (ie. =100 and = 25). What is the probability that a professor woul
Random Samples
Our purpose in drawing samples is to make inferences
about the populations from which our samples are drawn Random selection, however, will produce varying estimates from one sample to another But these multiple estimates (if we draw multi
X of Z: What's the # of times guys are rejected at a certain nightclub?
At a certain nightclub, the mean # of times ( ie.) men are rejected is 7 with a standard
deviation of 1.5.(ie. ) We want to know the rejection rate that is, say, 75% of all men are e
Facebook Assignment #2 : Making Meaningful Comparisons between Data Due March 10th A. The first assignment asked you to get measures of central tendency, the lower and upper quartiles, the IQR, and the range for the number of friends you have plus your "f