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Chapter 22. Statistics. #22. Business Statistics. Learning Unit Objectives. Mean, Median, and Mode. LU22.1. Define and calculate the mean Explain and calculate a weighted mean Define and calculate the median Define and identify the mode. #22. Business Statistics.
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Chapter 22 Statistics
#22 Business Statistics Learning Unit Objectives Mean, Median, and Mode LU22.1 • Define and calculate the mean • Explain and calculate a weighted mean • Define and calculate the median • Define and identify the mode
#22 Business Statistics Learning Unit Objectives Frequency Distributions and Graphs LU22.2 • Prepare a frequency distribution • Prepare bar, line, and circle graphs • Calculate price relatives and cost comparisons
#22 Business Statistics Learning Unit Objectives Measures of Dispersion (Optional Section) LU22.3 • Explain and calculate the range • Define and calculate the standard deviation • Estimate percentage of data by using standard deviations
Terminology Median - A measurement that indicates the center of the data (Average) Mean - Average used to indicate a single value that represents an entire group of numbers Mode - a measurement that records values. The value that occurs most often
Mean Mean = Sum of all values Number of values What is the mean of the following daily sales? Sun. Mon. Tues. Wed. Thur. Fri. Sat. $400 $100 $68 $115 $120 $68 $180 Mean = $400 + $100 + $68 + $115 + $120 +$68 + $180 = $150.14 7
Weighted Mean Weighted Mean = Sum of products Sum of frequencies What is the weighted mean (GPA) for the student? Credit Grade Points Courses attempted received (Credits x Grade) Intro to Comp 4 A 16 (4 x 4) Psychology 3 B 9 (3 x 3) English Comp. 3 B 9 (3 x 3) Business Law 3 C 6 (2 x 3) Business Math 3 B 9 (3 x 3) 16 49 49 = 3.1 16
Finding the Median of a Group of Values Step 1. Orderly arrange values from the smallest to the largest Find the median age 42, 35, 87, 23, 50 • Step 2. Find the middle value • Odd number of values: Median is the middle value. Divide the total number of numbers by 2. (5/2 = 2 ½). The next-higher number is the median. • B. Even number of values: Median is the average of the two middle values. 23, 35, 42, 50, 87 Find the median age 42, 35, 87, 50 35, 42, 50, 87 42 + 50 2 46
Mode The value that occurs most often If two or more numbers appear most often, you may have two or more modes. If all the values are different, there is no mode 3 is the mode since it is listed 4 times 3, 4, 5, 6, 3, 8, 9, 3, 5, 3
Frequency Distribution A way of collecting and organizing raw data Price of Tally Frequency Computer $1,000 llll 5 2,000 l 1 3,000 llll 5 4,000 l 1 5,000 ll 2 6,000 ll 2 7,000 l 1 8,000 l 1 9,000 l 1 10,000 l 1 Computer costs Frequency distribution table
Bar Graph Frequency of purchase 2000 4000 6000 8000 10000 Price of Computers
Bar Graph Class Frequency $1000 - $ 3,000.99 11 $3001 - 5,000.99 3 $5001 - 7,000.99 3 $8001 - 9,000.99 2 $9001 - 11,000.99 1 Frequency of purchase $3,001- $5,000.99 $7,001- $9,000.99
Line Graph Average cost of College tuition Year
Circle Graph 12.9% 12.9% 17.3% 56.9% Revenues 1st Qtr. $20,400 2nd Qtr $27,400 3rd Qtr $90,000 4th Qtr $20,400
Measure of Dispersion • Measure of Dispersion – a number that describes how the numbers of a set of data are spread out or dispersed. • Range – The difference between the two extreme values (highest and lowest) in a group of values or a set of data. Range = Highest value – Lowest value Find the range of the following values: 83.6, 77.3, 69.2, 93.1, 85.4, 71.6 Range = 93.1 – 69.2 = 23.9
Index Numbers Price relative = Current price x 100 Base year’s price A computer cost $850 today relative to a cost of $1,300 some 5 years ago. What is the relative price? $850 x 100 = 65.38 = 65.4 $1,300
Consumer Price Index (in percent) Expense Atlanta Chicago NY LA Food 131.9 130.3 139.6 130.9 Housing 128.8 131.4 139.3 139.3 Clothing 133.8 124.3 121.8 126.4 Medical care 177.6 163.0 172.4 163.3
Standard Deviation Intended to measure the spread of data around the mean Step 6. Find the square root ( ) of the number obtained in Step 5. This is the standard deviation Step 5. Divide the sum of the squared deviations by n - 1, where n equals the number of pieces of data Step 4. Sum all squared deviations Step 3. Square each deviation (multiply the deviation by itself) Step 2. Subtract the mean from each piece of data to find each deviation Step 1. Find the mean of the set of data
Standard Deviation Step 1(1 + 2 + 5 + 10 + 12) = 6 (Mean) 5 Step 2Step 3 Data Data-Mean (Data-Mean) 1 1- 6 = -5 25 2 2 - 6 = -4 16 5 5 - 6 = -1 1 10 10 - 6 = 4 16 12 12 - 6 = 636 Total 0 94 (Step 4) Step 5: Divide by n-1: 94 = 94 = 23.5 5-1 4 Step 6: The square root of 23.5 is 4.8 Data Set A x x x x x 0 1 2 3 4 5 6 7 8 9 10 11 12 13 The standard deviation of data set A is 4.8
Standard Deviation Step 1(4 + 4 + 5 + 8 + 9) = 6 (Mean) 5 Step 2Step 3 Data Data-Mean (Data-Mean) 1 4- 6 = -2 4 2 4 - 6 = -2 4 5 5 - 6 = -1 1 10 8 - 6 = 2 4 12 9 - 6 = 39 Total 0 22 (Step 4) Step 5: Divide by n-1: 22 = 22 = 5.5 5-1 4 Step 6: The square root of 5.5 is 2.3 Data Set B x x x x x 0 1 2 3 4 5 6 7 8 9 10 11 12 13 The standard deviation of data set A is 2.3
Problem 22-19 .35 x 360 = 126 .28 x 360 = 100.8 .20 x 360 = 72 .17 x 360 = 61.2 Misc. 17% Transportation 35% Food and entertainment 20% Hotel 28%
Problem 22-20 Frequency Intervals Tally Frequency $0- $5.99 5 5 $6- $11.99 3 3 $12- $17.99 4 4 $18- $23.99 2 2
Problem 22-21 Tally Day Bagels Product 150 9 9 x 150 = 1,350 190 4 4 x 290 = 760 200 6 6 x 200 = 1,200 360 5 5 x 360 = 1,800 400 6 6 x 400 = 2,400 7, 510 7,510/ 30 = 250.33= 250 Bagels
Problem 22-22 Thousands of dollars