The following scores represent the results of a midterm exam in Statistics class. 25 35 43 44 47 48 54 55 56 57 59 62 63 65 66 68 69 69 71 72 72 73 74 76 77 77 78 79 80 81 81 82 83 85 89 92 93 94 97 98 a) Find the lower and upper quartiles for the data. b) Find the interquartile range. c) Construct a boxplot for this data set.

Respuesta :

Answer:

a.

lower Quartile= 57.5

Upper Quartile=81

b.

23.5

c.

box-plot is attached in excel file

Step-by-step explanation:

The data is arranged in ascending order so, the lower quartile denoted as Q1 can be calculated as under

Q1=((n+1)/4)th score=(41/4)th score=(10.25)th score

Q1=10th score+0.25(11th-10th)score

Q1=57+0.25(59-57)=57+0.5=57.5

Q1=57.5

The data is arranged in ascending order so, the third quartile denoted as Q3 can be calculated as under

Q3=(3(n+1)/4)th score=(3*41/4)th score=(30.75)th score

Q3=30th score+0.75(31th-30th)score

Q3=81+0.75(81-81)=81+0=81

Q3=81

b)

Interquartile range=IQR=Q3-Q1=81-57.5=23.5

IQR=23.5

c)

The box-plot is made in excel and it shows no outlier. The box-plot shows the 5-number summary(minimum-Q1-median-Q3-maximum) as 25-57.5-72-81-98.

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