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Chapter 3 - Coggle Diagram

- - - - ): is the value that occurs with the highest frequency
      - . For categorical data, you have to use the mode.
    - - If p = 50 % then 50th percentile is the median value.
        
        How to determine pth percentile?
        
        Step 1: order the dataset from smallest to largest.
        
        Step 2: Compute index , where n is the number of observations.
        
        Step 3: Determine pth percentile value:
        
        Case #1: If i is an integer value( SỐ NGUYÊN), the pth percentile value is the average of values at the i and (i+1)th positions in the ordering dataset.
        
        Case #2: If i is not an integer value( SỐ KHÔNG NGUYÊN), we round up i. Then, the pth percentile value is the value at the ith position.
        
        BT
        
        4 more items...
        
        BT
        
        Step 1: done.
        
        ordering data: 5 10 10 20 (20 20) 20 25 30 30 30 35 40 40 40
        
        Step 2: We have
        
        Step 3: 40th percentile is the average of values at 6th and 7th positions
        
        If i is an integer value, the pth percentile value is the average of values at the i and (i+1)th positions in the ordering dataset.
        
        Explain: About 40% of students work less than 20 hours per week.
    - - is the middle value in an ordering data set.
        
        2 case
        
        odd value
        
        n=2m+1==>m+1 vd n=15 ---> m=7--->m+1=8
        
        tìm mid point ( nhớ săp sếp ở bước 1)
        
        btap
        
        n= 15 = 2*m + 1- m= 7-- m+1 =8
        
        Md = 25 hours.
        
        Explain: About 50% of students work less than 25 hours per week.
        
        The ordering data: 5 10 10 20 20 20 20 25 30 30 30 35 40 40 40
        
        even value
        
        n = 2*m
        
        sau đó position m+1 và tính trung bình của giá trị (m và m+1 )/2
        
        bt
        
        6 more items...
    - - Quartiles are values that divide an ordered data set into four parts approximately one fourth (25%)
      - Quartiles are specific percentiles:
        
        • The second quartile (Tứ phân vị thứ hai) (Q2) is the 50th percentile = median.
        
        • The third quartile (Tứ phân vị thứ ba) (Q3) is the 75th percentile
        
        • The first quartile (Q1)( Tứ phân vị thứ nhất) is the 25th percentile
        
        BT
        
        ordering data: 5 10 10 20 20 20 20 25 30 30 30 35 40 40 40
        
        Q1: ( 25th percentile)- p = 25
        
        Step 1: Done.
        
        Step 2: Compute i = p*n/100 = 25X15/100 = 3.75 ~ 4 ( due to not integer)
        
        Step 3: the pth percentile value is the value at the 4th position, Q1 = 20.
        
        Q2: ( 50th percentile)- p = 50
        
        Step 2: i = 50*15/100 = 7.5 ~8 (due to not integer)
        
        Step 3: the 50th percentile value is the value at the 8th position, Q2 = 25
        
        Explain: About 50% of students work less than 25 hours per week.
    - - population mean ( trung bình tổng thể) u
        
        is the averageof the population measurements.
        
        Often a population is very large,Therefore, we can not compute the population mean
        
        we must estimate the populationmean by using a sample of measurements
        
        we must realize that thepopulation mean is a population parameter.
        
        estimate a populationparameter is to make a point estimate.
        
        use a sample statistic.
        
        1 more item...
    - - use 2 case
        
        case 1
        
        table
        
        case 2
        
        a grouped-data where x1 is mid point = (x nhỏ + x lớn ):2